Programs & Examples On #Maven 2

Apache Maven is a software project management and comprehension tool. This is a tag for Maven related questions that are specific to Maven versions 2.x.

this.getClass().getClassLoader().getResource("...") and NullPointerException

I think I did encounter the same issue as yours. I created a simple mvn project and used "mvn eclipse:eclipse" to setup a eclipse project.

For example, my source file "Router.java" locates in "java/main/org/jhoh/mvc". And Router.java wants to read file "routes" which locates in "java/main/org/jhoh/mvc/resources"

I run "Router.java" in eclipse, and eclipse's console got NullPointerExeption. I set pom.xml with this setting to make all *.class java bytecode files locate in build directory.

<build>
    <defaultGoal>package</defaultGoal>
    <directory>${basedir}/build</directory>
<build>

I went to directory "build/classes/org/jhoh/mvc/resources", and there is no "routes". Eclipse DID NOT copy "routes" to "build/classes/org/jhoh/mvc/resources"

I think you can copy your "install.xml" to your *.class bytecode directory, NOT in your source code directory.

Run a single test method with maven

What I do with my TestNG, (sorry, JUnit doesn't support this) test cases is I can assign a group to the test I want to run

@Test(groups="broken")

And then simply run 'mvn -Dgroups=broken'.

Resource from src/main/resources not found after building with maven

Once after we build the jar will have the resource files under BOOT-INF/classes or target/classes folder, which is in classpath, use the below method and pass the file under the src/main/resources as method call getAbsolutePath("certs/uat_staging_private.ppk"), even we can place this method in Utility class and the calling Thread instance will be taken to load the ClassLoader to get the resource from class path.

 public String getAbsolutePath(String fileName) throws IOException {
      return Thread.currentThread().getContextClassLoader().getResource(fileName).getFile();
  }

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we can add the below tag to tag in pom.xml to include these resource files to build target/classes folder

<resources>
        <resource>
            <directory>src/main/resources</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.ppk</include>
            </includes>
        </resource>
</resources>

How can I download a specific Maven artifact in one command line?

You could use the maven dependency plugin which has a nice dependency:get goal since version 2.1. No need for a pom, everything happens on the command line.

To make sure to find the dependency:get goal, you need to explicitly tell maven to use the version 2.1, i.e. you need to use the fully qualified name of the plugin, including the version:

mvn org.apache.maven.plugins:maven-dependency-plugin:2.1:get \
    -DrepoUrl=url \
    -Dartifact=groupId:artifactId:version

UPDATE: With older versions of Maven (prior to 2.1), it is possible to run dependency:get normally (without using the fully qualified name and version) by forcing your copy of maven to use a given version of a plugin.

This can be done as follows:

1. Add the following line within the <settings> element of your ~/.m2/settings.xml file:

<usePluginRegistry>true</usePluginRegistry>

2. Add the file ~/.m2/plugin-registry.xml with the following contents:

<?xml version="1.0" encoding="UTF-8"?>
<pluginRegistry xsi:schemaLocation="http://maven.apache.org/PLUGIN_REGISTRY/1.0.0 http://maven.apache.org/xsd/plugin-registry-1.0.0.xsd"
xmlns="http://maven.apache.org/PLUGIN_REGISTRY/1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-dependency-plugin</artifactId>
      <useVersion>2.1</useVersion>
      <rejectedVersions/>
    </plugin>
  </plugins>
</pluginRegistry>

But this doesn't seem to work anymore with maven 2.1/2.2. Actually, according to the Introduction to the Plugin Registry, features of the plugin-registry.xml have been redesigned (for portability) and the plugin registry is currently in a semi-dormant state within Maven 2. So I think we have to use the long name for now (when using the plugin without a pom, which is the idea behind dependency:get).

Maven dependency for Servlet 3.0 API?

I'd prefer to only add the Servlet API as dependency,

To be honest, I'm not sure to understand why but never mind...

Brabster separate dependencies have been replaced by Java EE 6 Profiles. Is there a source that confirms this assumption?

The maven repository from Java.net indeed offers the following artifact for the WebProfile:

<repositories>
  <repository>
    <id>java.net2</id>
    <name>Repository hosting the jee6 artifacts</name>
    <url>http://download.java.net/maven/2</url>
  </repository>
</repositories>        
<dependencies>
  <dependency>
    <groupId>javax</groupId>
    <artifactId>javaee-web-api</artifactId>
    <version>6.0</version>
    <scope>provided</scope>
  </dependency>
</dependencies>

This jar includes Servlet 3.0, EJB Lite 3.1, JPA 2.0, JSP 2.2, EL 1.2, JSTL 1.2, JSF 2.0, JTA 1.1, JSR-45, JSR-250.

But to my knowledge, nothing allows to say that these APIs won't be distributed separately (in java.net repository or somewhere else). For example (ok, it may a particular case), the JSF 2.0 API is available separately (in the java.net repository):

<dependency>
   <groupId>com.sun.faces</groupId>
   <artifactId>jsf-api</artifactId>
   <version>2.0.0-b10</version>
   <scope>provided</scope>
</dependency>

And actually, you could get javax.servlet-3.0.jar from there and install it in your own repository.

'mvn' is not recognized as an internal or external command, operable program or batch file

Place the full path to mvn in your PATH environment variable.

Setting Java heap space under Maven 2 on Windows

It should be the same command, except SET instead of EXPORT

  • set MAVEN_OPTS=-Xmx512m would give it 512Mb of heap
  • set MAVEN_OPTS=-Xmx2048m would give it 2Gb of heap

Maven parent pom vs modules pom

There is one little catch with the third approach. Since aggregate POMs (myproject/pom.xml) usually don't have parent at all, they do not share configuration. That means all those aggregate POMs will have only default repositories.

That is not a problem if you only use plugins from Central, however, this will fail if you run plugin using the plugin:goal format from your internal repository. For example, you can have foo-maven-plugin with the groupId of org.example providing goal generate-foo. If you try to run it from the project root using command like mvn org.example:foo-maven-plugin:generate-foo, it will fail to run on the aggregate modules (see compatibility note).

Several solutions are possible:

  1. Deploy plugin to the Maven Central (not always possible).
  2. Specify repository section in all of your aggregate POMs (breaks DRY principle).
  3. Have this internal repository configured in the settings.xml (either in local settings at ~/.m2/settings.xml or in the global settings at /conf/settings.xml). Will make build fail without those settings.xml (could be OK for large in-house projects that are never supposed to be built outside of the company).
  4. Use the parent with repositories settings in your aggregate POMs (could be too many parent POMs?).

Including dependencies in a jar with Maven

Putting Maven aside, you can put JAR libraries inside the Main Jar but you will need to use your own classloader.

Check this project: One-JAR link text

Specify JDK for Maven to use

compile:compile has a user property that allows you to specify a path to the javac.

Note that this user property only works when fork is true which is false by default.

$ mvn -Dmaven.compiler.fork=true -Dmaven.compiler.executable=/path/to/the/javac compile

You might have to double quote the value if it contains spaces.

> mvn -Dmaven.compiler.fork=true -Dmaven.compiler.executable="C:\...\javac" compile

See also Maven custom properties precedence.

Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.10:test

please follow this tutorial: https://www.petrikainulainen.net/programming/maven/creating-code-coverage-reports-for-unit-and-integration-tests-with-the-jacoco-maven-plugin/

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.15</version>
<configuration>
    <!-- Sets the VM argument line used when unit tests are run. -->
    <argLine>${surefireArgLine}</argLine>
    <!-- Skips unit tests if the value of skip.unit.tests property is true -->
    <skipTests>${skip.unit.tests}</skipTests>
    <!-- Excludes integration tests when unit tests are run. -->
    <excludes>
        <exclude>**/IT*.java</exclude>
    </excludes>
</configuration>

Maven won't run my Project : Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:exec

Try to run Maven from the command line or type "-X" in the text field - you can't break anything this way, at the worst, you'll get an error (I don't have Netbeans; in Eclipse, there is a checkbox "Debug" for this).

When running with debug output enabled, you should see the paths which the exec-maven-plugin plugin uses.

The next step would then be to copy the command into a command prompt or terminal and execute it manually to see if you get a useful error message there.

How to change maven logging level to display only warning and errors?

Changing the info to error in simplelogging.properties file will help in achieving your requirement.

Just change the value of the below line

org.slf4j.simpleLogger.defaultLogLevel=info 

to

org.slf4j.simpleLogger.defaultLogLevel=error

How to specify maven's distributionManagement organisation wide?

Regarding the answer from Michael Wyraz, where you use alt*DeploymentRepository in your settings.xml or command on the line, be careful if you are using version 3.0.0-M1 of the maven-deploy-plugin (which is the latest version at the time of writing), there is a bug in this version that could cause a server authentication issue.

A workaround is as follows. In the value:

releases::default::https://YOUR_NEXUS_URL/releases

you need to remove the default section, making it:

releases::https://YOUR_NEXUS_URL/releases

The prior version 2.8.2 does not have this bug.

Maven: Command to update repository after adding dependency to POM

If you want to only download dependencies without doing anything else, then it's:

mvn dependency:resolve

Or to download a single dependency:

mvn dependency:get -Dartifact=groupId:artifactId:version

If you need to download from a specific repository, you can specify that with -DrepoUrl=...

Is there a simple way to remove unused dependencies from a maven pom.xml?

As others have said, you can use the dependency:analyze goal to find which dependencies are used and declared, used and undeclared, or unused and declared. You may also find dependency:analyze-dep-mgt useful to look for mismatches in your dependencyManagement section.

You can simply remove unwanted direct dependencies from your POM, but if they are introduced by third-party jars, you can use the <exclusions> tags in a dependency to exclude the third-party jars (see the section titled Dependency Exclusions for details and some discussion). Here is an example excluding commons-logging from the Spring dependency:

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring</artifactId>
  <version>2.5.5</version>
  <exclusions>
    <exclusion>
      <groupId>commons-logging</groupId>
      <artifactId>commons-logging</artifactId>
    </exclusion>
  </exclusions> 
</dependency>

Where is Maven's settings.xml located on Mac OS?

After I have downloaded the binary from apache site I, have placed the extracted folder in /Library
So now the location of the settings.xml file is in:

/Library/apache_maven_3.6.3/conf

Specify system property to Maven project

I have learned it is also possible to do this with the exec-maven-plugin if you're doing a "standalone" java app.

            <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>exec-maven-plugin</artifactId>
            <version>${maven.exec.plugin.version}</version>
            <executions>
                <execution>
                    <goals>
                        <goal>java</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <mainClass>${exec.main-class}</mainClass>
                <systemProperties>
                    <systemProperty>
                        <key>myproperty</key>
                        <value>myvalue</value>
                    </systemProperty>
                </systemProperties>
            </configuration>
        </plugin>

How to manually install an artifact in Maven 2?

You need to indicate the groupId, the artifactId and the version for your artifact:

mvn install:install-file \
  -DgroupId=javax.transaction \
  -DartifactId=jta \
  -Dpackaging=jar \
  -Dversion=1.0.1B \
  -Dfile=jta-1.0.1B.jar \
  -DgeneratePom=true

Unable to install Maven on Windows: "JAVA_HOME is set to an invalid directory"

Sometimes in Windows whitespaces in paths are not recognized correctly

If you have a path problem and path seems like

c:\Program Files\....

try changing it in an old DOS format like

"C:\Progra~1\...

You can use dir /x to check correct syntax (third column)

C:\>dir /x ... 11.01.2008 15:47 <DIR> DOCUME~1 Documents and Settings 01.12.2006 09:10 <DIR> MYPROJ~1 My Projects 21.01.2011 14:08 <DIR> PROGRA~1 Program Files ...

In my pc JAVA_HOME is (and it works)

"C:\Progra~1\Java\jdk1.8.0_121"

Tested in Windows 10

Which maven dependencies to include for spring 3.0?

You can add spring-context dependency for spring jars. You will get the following jars along with it.

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.0.5.RELEASE</version>
</dependency>

Spring context dependencies

if you also want web components, you can use spring-webmvc dependency.

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.0.5.RELEASE</version>
</dependency>

Spring webmvc dependencies

You can use whatever version of that you want. I have used 5.0.5.RELEASE here.

Retrieve version from maven pom.xml in code

With reference to ketankk's answer:

Unfortunately, adding this messed with how my application dealt with resources:

<build>
  <resources>
    <resource>
      <directory>src/main/resources</directory>
      <filtering>true</filtering>
    </resource>
  </resources>   
</build>

But using this inside maven-assemble-plugin's < manifest > tag did the trick:

<addDefaultImplementationEntries>true</addDefaultImplementationEntries>
<addDefaultSpecificationEntries>true</addDefaultSpecificationEntries>

So I was able to get version using

String version = getClass().getPackage().getImplementationVersion();

Find Oracle JDBC driver in Maven repository

You can use Nexus to manage 3rd party dependencies as well as dependencies in standard maven repositories.

m2eclipse not finding maven dependencies, artifacts not found

For me maven was downloading the dependency but was unable to add it to the classpath. I saw my .classpath of the project,it didnt have any maven-related entry. When I added

<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER"/>

the issue got resolved for me.

Eclipse - java.lang.ClassNotFoundException

This was my solution to the problem. Of course, many things can cause it to occur. For me it was that Maven2 (not the plugin for Eclipse) was setting the eclipse profile up to use a different builder (aspectJ) but I did not have the plugin in eclipse./

http://rbtech.blogspot.com/2009/09/eclipse-galileo-javalangclassnotfoundex.html

Cheers Ramon Buckland

How do I execute a program using Maven?

With the global configuration that you have defined for the exec-maven-plugin:

<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>exec-maven-plugin</artifactId>
  <version>1.4.0</version>
  <configuration>
    <mainClass>org.dhappy.test.NeoTraverse</mainClass>
  </configuration>
</plugin>

invoking mvn exec:java on the command line will invoke the plugin which is configured to execute the class org.dhappy.test.NeoTraverse.

So, to trigger the plugin from the command line, just run:

mvn exec:java

Now, if you want to execute the exec:java goal as part of your standard build, you'll need to bind the goal to a particular phase of the default lifecycle. To do this, declare the phase to which you want to bind the goal in the execution element:

<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>exec-maven-plugin</artifactId>
  <version>1.4</version>
  <executions>
    <execution>
      <id>my-execution</id>
      <phase>package</phase>
      <goals>
        <goal>java</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <mainClass>org.dhappy.test.NeoTraverse</mainClass>
  </configuration>
</plugin>

With this example, your class would be executed during the package phase. This is just an example, adapt it to suit your needs. Works also with plugin version 1.1.

Maven: best way of linking custom external JAR to my project?

With Eclipse Oxygen you can do the below things:

  1. Place your libraries in WEB-INF/lib
  2. Project -> Configure Build Path -> Add Library -> Web App Library

Maven will take them when installing the project.

Importing Maven project into Eclipse

I was unable to import a Maven project with the steps suggested above until I figured out why it was not importing:

A maven project will not import if you have another Maven project with the same artifact id. Make sure that your project's artifact ID is unique in your eclipse workspace.

Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.12:test (default-test) on project.

Just add those below line in pom.xml file on the top of <modelversion> tag:

<repositories>
  <repository>
    <id>central</id>
    <name>Central Repository</name>
    <url>http://repo.maven.apache.org/maven2</url>
    <layout>default</layout>
    <snapshots>
      <enabled>false</enabled>
    </snapshots>
  </repository>
</repositories>

Sample settings.xml

A standard Maven settings.xml file is as follows:

<settings xmlns="http://maven.apache.org/SETTINGS/1.1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.1.0 http://maven.apache.org/xsd/settings-1.1.0.xsd">
  <localRepository/>
  <interactiveMode/>
  <usePluginRegistry/>
  <offline/>

  <proxies>
    <proxy>
      <active/>
      <protocol/>
      <username/>
      <password/>
      <port/>
      <host/>
      <nonProxyHosts/>
      <id/>
    </proxy>
  </proxies>

  <servers>
    <server>
      <username/>
      <password/>
      <privateKey/>
      <passphrase/>
      <filePermissions/>
      <directoryPermissions/>
      <configuration/>
      <id/>
    </server>
  </servers>

  <mirrors>
    <mirror>
      <mirrorOf/>
      <name/>
      <url/>
      <layout/>
      <mirrorOfLayouts/>
      <id/>
    </mirror>
  </mirrors>

  <profiles>
    <profile>
      <activation>
        <activeByDefault/>
        <jdk/>
        <os>
          <name/>
          <family/>
          <arch/>
          <version/>
        </os>
        <property>
          <name/>
          <value/>
        </property>
        <file>
          <missing/>
          <exists/>
        </file>
      </activation>
      <properties>
        <key>value</key>
      </properties>

      <repositories>
        <repository>
          <releases>
            <enabled/>
            <updatePolicy/>
            <checksumPolicy/>
          </releases>
          <snapshots>
            <enabled/>
            <updatePolicy/>
            <checksumPolicy/>
          </snapshots>
          <id/>
          <name/>
          <url/>
          <layout/>
        </repository>
      </repositories>
      <pluginRepositories>
        <pluginRepository>
          <releases>
            <enabled/>
            <updatePolicy/>
            <checksumPolicy/>
          </releases>
          <snapshots>
            <enabled/>
            <updatePolicy/>
            <checksumPolicy/>
          </snapshots>
          <id/>
          <name/>
          <url/>
          <layout/>
        </pluginRepository>
      </pluginRepositories>
      <id/>
    </profile>
  </profiles>

  <activeProfiles/>
  <pluginGroups/>
</settings>

To access a proxy, you can find detailed information on the official Maven page here:

Maven-Settings - Settings

I hope it helps for someone.

A cycle was detected in the build path of project xxx - Build Path Problem

Mark circular dependencies as "Warning" in Eclipse tool to avoid "A CYCLE WAS DETECTED IN THE BUILD PATH" error.

In Eclipse go to:

Windows -> Preferences -> Java-> Compiler -> Building -> Circular Dependencies

List all of the possible goals in Maven 2?

A Build Lifecycle is Made Up of Phases

Each of these build lifecycles is defined by a different list of build phases, wherein a build phase represents a stage in the lifecycle.

For example, the default lifecycle comprises of the following phases (for a complete list of the lifecycle phases, refer to the Lifecycle Reference):

  • validate - validate the project is correct and all necessary information is available
  • compile - compile the source code of the project
  • test - test the compiled source code using a suitable unit testing framework. These tests should not require the code be packaged or deployed
  • package - take the compiled code and package it in its distributable format, such as a JAR. verify - run any checks on results of integration tests to ensure quality criteria are met
  • install - install the package into the local repository, for use as a dependency in other projects locally
  • deploy - done in the build environment, copies the final package to the remote repository for sharing with other developers and projects.

These lifecycle phases (plus the other lifecycle phases not shown here) are executed sequentially to complete the default lifecycle. Given the lifecycle phases above, this means that when the default lifecycle is used, Maven will first validate the project, then will try to compile the sources, run those against the tests, package the binaries (e.g. jar), run integration tests against that package, verify the integration tests, install the verified package to the local repository, then deploy the installed package to a remote repository.

Source: https://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html

"Unmappable character for encoding UTF-8" error

"error: unmappable character for encoding UTF-8" means, java has found a character which is not representing in UTF-8. Hence open the file in an editor and set the character encoding to UTF-8. You should be able to find a character which is not represented in UTF-8.Take off this character and recompile.

Git Ignores and Maven targets

The .gitignore file in the root directory does apply to all subdirectories. Mine looks like this:

.classpath
.project
.settings/
target/

This is in a multi-module maven project. All the submodules are imported as individual eclipse projects using m2eclipse. I have no further .gitignore files. Indeed, if you look in the gitignore man page:

Patterns read from a .gitignore file in the same directory as the path, or in any parent directory

So this should work for you.

Maven: How to change path to target directory from command line?

Colin is correct that a profile should be used. However, his answer hard-codes the target directory in the profile. An alternate solution would be to add a profile like this:

    <profile>
        <id>alternateBuildDir</id>
        <activation>
            <property>
                <name>alt.build.dir</name>
            </property>
        </activation>
        <build>
            <directory>${alt.build.dir}</directory>
        </build>
    </profile>

Doing so would have the effect of changing the build directory to whatever is given by the alt.build.dir property, which can be given in a POM, in the user's settings, or on the command line. If the property is not present, the compilation will happen in the normal target directory.

What causes imported Maven project in Eclipse to use Java 1.5 instead of Java 1.6 by default and how can I ensure it doesn't?

Project specific settings

One more place where this can go wrong is in the project specific settings, in Eclipse.

  1. project properties: click your project and one of the following:

    • Alt + Enter
    • Menu > Project > Properties
    • right click your project > project properties (last item in the menu)
  2. click on "Java Compiler"

  3. Uncheck "Enable project specific settings" (or change them all by hand).

Because of client requirements we had them enabled to keep our projects in 1.6. When it was needed to upgrade to 1.7, we had a hard time because we needed to change the java version all over the place:

  • project POM
  • Eclipse Workspace default
  • project specific settings
  • executing virtual machine (1.6 was used for everything)

How do I set the eclipse.ini -vm option?

The JDK you're pointing to in your eclipse.ini has to match the Eclipse installation.

If you are running a 32- or 64-bit Eclipse, use a 32 or 64-bit Java JDK, respectively.

JUnit tests pass in Eclipse but fail in Maven Surefire

This doesn't exactly apply to your situation, but I had the same thing -- tests that would pass in Eclipse failed when the test goal from Maven was run.

It turned out to be a test earlier in my suite, in a different package. This took me a week to solve!

An earlier test was testing some Logback classes, and created a Logback context from a config file.

The later test was testing a subclass of Spring's SimpleRestTemplate, and somehow, the earlier Logback context was held, with DEBUG on. This caused extra calls to be made in RestTemplate to log HttpStatus, etc.

It's another thing to check if one ever gets into this situation. I fixed my problem by injecting some Mocks into my Logback test class, so that no real Logback contexts were created.

build maven project with propriatery libraries included

Possible solutions is put your dependencies in src/main/resources then in your pom :

<dependency>
groupId ...
artifactId ...
version ...
<scope>system</scope>
<systemPath>${project.basedir}/src/main/resources/yourJar.jar</systemPath>
</dependency>

Note: system dependencies are not copied into resulted jar/war
(see How to include system dependencies in war built using maven)

Maven2 property that indicates the parent directory

You are in project C, project C is submodule of B and B is submodule of A. You try to reach module D's src/test/config/etc directory from project C. D is also submodule of A. The following expression makes this possible to get the URI path:

-Dparameter=file:/${basedir}/../../D/src/test/config/etc

maven compilation failure

You could try running the "mvn site" command and see what transitive dependencies you have, and then resolve potential conflicts (by ommitting an implicit dependency somewhere). Just a guess (it's a bit difficult to know what the problem could be without seeing your pom info)...

Add a dependency in Maven

I'd do this:

  1. add the dependency as you like in your pom:

    <dependency>
            <groupId>com.stackoverflow...</groupId>
            <artifactId>artifactId...</artifactId>
            <version>1.0</version>
    </dependency>
    

  2. run mvn install it will try to download the jar and fail. On the process, it will give you the complete command of installing the jar with the error message. Copy that command and run it! easy huh?!

The following artifacts could not be resolved: javax.jms:jms:jar:1.1

A check of ibliblio and java.net repositories reveal that jmx related jar is not present in either. I think you should manually download jms and install them locally as discussed here.

Load properties file in JAR?

For the record, this is documented in How do I add resources to my JAR? (illustrated for unit tests but the same applies for a "regular" resource):

To add resources to the classpath for your unit tests, you follow the same pattern as you do for adding resources to the JAR except the directory you place resources in is ${basedir}/src/test/resources. At this point you would have a project directory structure that would look like the following:

my-app
|-- pom.xml
`-- src
    |-- main
    |   |-- java
    |   |   `-- com
    |   |       `-- mycompany
    |   |           `-- app
    |   |               `-- App.java
    |   `-- resources
    |       `-- META-INF
    |           |-- application.properties
    `-- test
        |-- java
        |   `-- com
        |       `-- mycompany
        |           `-- app
        |               `-- AppTest.java
        `-- resources
            `-- test.properties

In a unit test you could use a simple snippet of code like the following to access the resource required for testing:

...

// Retrieve resource
InputStream is = getClass().getResourceAsStream("/test.properties" );

// Do something with the resource

...

Differences between Ant and Maven

I can take a person that has never seen Ant - its build.xmls are reasonably well-written - and they can understand what is going on. I can take that same person and show them a Maven POM and they will not have any idea what is going on.

In an engineering organization that is huge, people write about Ant files becoming large and unmanageable. I've written those types and clean Ant scripts. It's really understanding upfront what you need to do going forward and designing a set of templates that can respond to change and scale over a 3+ year period.

Unless you have a simple project, learning the Maven conventions and the Maven way about getting things done is quite a bit of work.

At the end of the day you cannot consider project startup with Ant or Maven a factor: it's really the total cost of ownership. What it takes for the organization to maintain and extend its build system over a few years is one of the main factors that must be considered.

The most important aspects of a build system are dependency management and flexibility in expressing the build recipe. It must be somewhat intuitive when done well.

Warning - Build path specifies execution environment J2SE-1.4

I met the same warning in STS (Spring Tool Suite), if it may help someone somehow.

This is the source https://www.baeldung.com/eclipse-change-java-version, and here's a summary of it :

Warning : build path specifies execution environment javase-11. there are no jres installed in the workspace that are strictly compatible with this environment.

Environment : Ubuntu 20.04 (with default OpenJDK11) STS 4

To solve the warning :

  1. Change the JRE of the workspace of STS (By default, STS uses the JRE embedded in its plugins) : Window>Preferences>Installed JREs>Add>Standard VM>Directory (browse to your openjdk folder, in my case /usr/lib/jvm/java-11-openjdk-amd64)>Finish)
  2. Check the new JRE, then Apply and close
  3. Now configure the spring-boot project to use the newly added JRE : Right click on the project > properties > Java Build Path > in Libraries tab > Remove the old JRE, then in Modulepath Add Library > JRE System Library > Environments (choose JavaSE-11, make sure to check it on the right panel, mentionned "perfect-match"), Apply and Close

And voilà

Maven Error: Could not find or load main class

For me the problem was nothing to do with Maven but to do with how I was running the .jar. I wrote some code and packaged it as a .jar with Maven. I ran it with

java target/gs-maven-0.1.0.jar

and got the error in the OP. Actually you need the -jar option:

java -jar target/gs-maven-0.1.0.jar

Controlling Maven final name of jar artifact

@Maxim
try this...

pom.xml

 <groupId>org.opensource</groupId>
 <artifactId>base</artifactId>
 <version>1.0.0.SNAPSHOT</version>

  ..............
<properties>
    <my.version>4.0.8.8</my.version>
</properties>

<build>
    <finalName>my-base-project</finalName>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-install-plugin</artifactId>
            <version>2.3.1</version>
            <executions>
                <execution>
                    <goals>
                        <goal>install-file</goal>
                    </goals>
                    <phase>install</phase>
                    <configuration>
                        <file>${project.build.finalName}.${project.packaging}</file>
                        <generatePom>false</generatePom>
                        <pomFile>pom.xml</pomFile>
                        <version>${my.version}</version>
                    </configuration>
                </execution>
            </executions>
        </plugin>
</plugins>
</build>

Commnad mvn clean install

Output

[INFO] --- maven-jar-plugin:2.3.1:jar (default-jar) @ base ---
[INFO] Building jar: D:\dev\project\base\target\my-base-project.jar
[INFO]
[INFO] --- maven-install-plugin:2.3.1:install (default-install) @ base ---
[INFO] Installing D:\dev\project\base\target\my-base-project.jar to H:\dev\.m2\repository\org\opensource\base\1.0.0.SNAPSHOT\base-1.0.0.SNAPSHOT.jar
[INFO] Installing D:\dev\project\base\pom.xml to H:\dev\.m2\repository\org\opensource\base\1.0.0.SNAPSHOT\base-1.0.0.SNAPSHOT.pom
[INFO]
[INFO] --- maven-install-plugin:2.3.1:install-file (default) @ base ---
[INFO] Installing D:\dev\project\base\my-base-project.jar to H:\dev\.m2\repository\org\opensource\base\4.0.8.8\base-4.0.8.8.jar
[INFO] Installing D:\dev\project\base\pom.xml to H:\dev\.m2\repository\org\opensource\base\4.0.8.8\base-4.0.8.8.pom
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------


Reference

Plugin org.apache.maven.plugins:maven-clean-plugin:2.5 or one of its dependencies could not be resolved

I have faced the same issue. I have changed the maven-assembly-plugin to 3.1.1 from 2.5.3 in POM.xml

Proposed version should be done under plugin section. enter code here artifact Id for maven-assembly-plugin

Can I add jars to maven 2 build classpath without installing them?

Maven install plugin has command line usage to install a jar into the local repository, POM is optional but you will have to specify the GroupId, ArtifactId, Version and Packaging (all the POM stuff).

Spring 3.0 - Unable to locate Spring NamespaceHandler for XML schema namespace [http://www.springframework.org/schema/security]

The solution is definitely "spring-security-config" not in your WEB-INF/lib.

For my project in Eclipse using Maven, it turned out not all of the maven dependencies were being copied to WEB-INF/lib. Looking at Project -> Properties -> Deployment Assembly, only some of the jars were being copied.

To fix this, I clicked "Add", then "Java Build Path Entires" and finally "Maven Dependencies".

I have been searching SO and the web for the last hour looking for this, so hopefully this helps someone else.

How do I tell Maven to use the latest version of a dependency?

The dependencies syntax is located at the Dependency Version Requirement Specification documentation. Here it is is for completeness:

Dependencies' version element define version requirements, used to compute effective dependency version. Version requirements have the following syntax:

  • 1.0: "Soft" requirement on 1.0 (just a recommendation, if it matches all other ranges for the dependency)
  • [1.0]: "Hard" requirement on 1.0
  • (,1.0]: x <= 1.0
  • [1.2,1.3]: 1.2 <= x <= 1.3
  • [1.0,2.0): 1.0 <= x < 2.0
  • [1.5,): x >= 1.5
  • (,1.0],[1.2,): x <= 1.0 or x >= 1.2; multiple sets are comma-separated
  • (,1.1),(1.1,): this excludes 1.1 (for example if it is known not to work in combination with this library)

In your case, you could do something like <version>[1.2.3,)</version>

Do you know the Maven profile for mvnrepository.com?

Place this in the ~/.m2/settings.xml or custom file to be run with $ mvn -s custom-settings.xml install

<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0
https://maven.apache.org/xsd/settings-1.0.0.xsd">
<localRepository>${user.home}/.m2/repository</localRepository>
<interactiveMode/>
<offline/>
<pluginGroups/>
<profiles>
    <profile>
        <repositories>
            <repository>
                <id>mvnrepository</id>
                <name>mvnrepository</name>
                <url>http://www.mvnrepository.com</url>
            </repository>
        </repositories>
    </profile>
</profiles>
<activeProfiles>
    <activeProfile>mvnrepository</activeProfile>
</activeProfiles>
</settings>

Where is my m2 folder on Mac OS X Mavericks

By default it will be hidden in your home directory. Type ls -a ~ to view that.

Maven compile with multiple src directories

You can add a new source directory with build-helper:

<build>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>build-helper-maven-plugin</artifactId>
            <version>3.2.0</version>
            <executions>
                <execution>
                    <phase>generate-sources</phase>
                    <goals>
                        <goal>add-source</goal>
                    </goals>
                    <configuration>
                        <sources>
                            <source>src/main/generated</source>
                        </sources>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

What is the difference between "mvn deploy" to a local repo and "mvn install"?

Ken, good question. I should be more explicit in the The Definitive Guide about the difference. "install" and "deploy" serve two different purposes in a build. "install" refers to the process of installing an artifact in your local repository. "deploy" refers to the process of deploying an artifact to a remote repository.

Example:

  1. When I run a large multi-module project on a my machine, I'm going to usually run "mvn install". This is going to install all of the generated binary software artifacts (usually JARs) in my local repository. Then when I build individual modules in the build, Maven is going to retrieve the dependencies from the local repository.

  2. When it comes time to deploy snapshots or releases, I'm going to run "mvn deploy". Running this is going to attempt to deploy the files to a remote repository or server. Usually I'm going to be deploying to a repository manager such as Nexus

It is true that running "deploy" is going to require some extra configuration, you are going to have to supply a distributionManagement section in your POM.

How to configure encoding in Maven?

In my case I was using the maven-dependency-plugin so in order to resolve the issue I had to add the following property:

  <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

See Apache Maven Resources Plugin / Specifying a character encoding scheme

Making Maven run all tests, even when some fail

I just found the "-fae" parameter, which causes Maven to run all tests and not stop on failure.

Missing Maven dependencies in Eclipse project

for me issue was due to multi module project .

  1. delete project from disk
  2. checkout project from your repo and import as maven project in eclipse
  3. clean install

How can I get Maven to stop attempting to check for updates for artifacts from a certain group from maven-central-repo?

The updatePolicy tag didn't work for me. However Rich Seller mentioned that snapshots should be disabled anyways so I looked further and noticed that the extra repository that I added to my settings.xml was causing the problem actually. Adding the snapshots section to this repository in my settings.xml did the trick!

<repository>
    <id>jboss</id>
    <name>JBoss Repository</name>
    <url>http://repository.jboss.com/maven2</url>
    <snapshots>
        <enabled>false</enabled>
    </snapshots>
</repository>

Disable a Maven plugin defined in a parent POM

The following works for me when disabling Findbugs in a child POM:

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>findbugs-maven-plugin</artifactId>
    <executions>
        <execution>
            <id>ID_AS_IN_PARENT</id> <!-- id is necessary sometimes -->
            <phase>none</phase>
        </execution>
    </executions>
</plugin>

Note: the full definition of the Findbugs plugin is in our parent/super POM, so it'll inherit the version and so-on.

In Maven 3, you'll need to use:

 <configuration>
      <skip>true</skip>
 </configuration>

for the plugin.

Maven:Non-resolvable parent POM and 'parent.relativePath' points at wrong local POM

There was conflict in java version. Resolved after using 1.8 for maven.

Maven2: Best practice for Enterprise Project (EAR file)

i have made a github repository to show what i think is a good (or best practices) startup project structure...

https://github.com/StefanHeimberg/stackoverflow-1134894

some keywords:

  • Maven 3
  • BOM (DependencyManagement of own dependencies)
  • Parent for all Projects (DependencyManagement from external dependencies and PluginManagement for global Project configuration)
  • JUnit / Mockito / DBUnit
  • Clean War project without WEB-INF/lib because dependencies are in EAR/lib folder.
  • Clean Ear project.
  • Minimal deployment descriptors for Java EE7
  • No Local EJB Interface because @LocalBean is sufficient.
  • Minimal maven configuration through maven user properties
  • Actual Deployment Descriptors for Servlet 3.1 / EJB 3.2 / JPA 2.1
  • usage of macker-maven-plugin to check architecture rules
  • Integration Tests enabled, but skipped. (skipITs=false) useful to enable on CI Build Server

Maven Output:

Reactor Summary:

MyProject - BOM .................................... SUCCESS [  0.494 s]
MyProject - Parent ................................. SUCCESS [  0.330 s]
MyProject - Common ................................. SUCCESS [  3.498 s]
MyProject - Persistence ............................ SUCCESS [  1.045 s]
MyProject - Business ............................... SUCCESS [  1.233 s]
MyProject - Web .................................... SUCCESS [  1.330 s]
MyProject - Application ............................ SUCCESS [  0.679 s]
------------------------------------------------------------------------
BUILD SUCCESS
------------------------------------------------------------------------
Total time: 8.817 s
Finished at: 2015-01-27T00:51:59+01:00
Final Memory: 24M/207M
------------------------------------------------------------------------

Create local maven repository

Set up a simple repository using a web server with its default configuration. The key is the directory structure. The documentation does not mention it explicitly, but it is the same structure as a local repository.

To set up an internal repository just requires that you have a place to put it, and then start copying required artifacts there using the same layout as in a remote repository such as repo.maven.apache.org. Source

Add a file to your repository like this:

mvn install:install-file \
  -Dfile=YOUR_JAR.jar -DgroupId=YOUR_GROUP_ID 
  -DartifactId=YOUR_ARTIFACT_ID -Dversion=YOUR_VERSION \
  -Dpackaging=jar \
  -DlocalRepositoryPath=/var/www/html/mavenRepository

If your domain is example.com and the root directory of the web server is located at /var/www/html/, then maven can find "YOUR_JAR.jar" if configured with <url>http://example.com/mavenRepository</url>.

How do I get my Maven Integration tests to run

Another way of running integration tests with Maven is to make use of the profile feature:

...
<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            <configuration>
                <includes>
                    <include>**/*Test.java</include>
                </includes>
                <excludes>
                    <exclude>**/*IntegrationTest.java</exclude>
                </excludes>
            </configuration>
        </plugin>
    </plugins>
</build>

<profiles>
    <profile>
        <id>integration-tests</id>
        <build>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <configuration>
                        <includes>
                            <include>**/*IntegrationTest.java</include>
                        </includes>
                        <excludes>
                            <exclude>**/*StagingIntegrationTest.java</exclude>
                        </excludes>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    </profile>
</profiles>
...

Running 'mvn clean install' will run the default build. As specified above integration tests will be ignored. Running 'mvn clean install -P integration-tests' will include the integration tests (I also ignore my staging integration tests). Furthermore, I have a CI server that runs my integration tests every night and for that I issue the command 'mvn test -P integration-tests'.

java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet

You need to add the "Maven Dependency" in the Deployment Assembly

  • right click on your project and choose properties.
  • click on Deployment Assembly.
  • click add
  • click on "Java Build Path Entries"
  • select Maven Dependencies"
  • click Finish.

Rebuild and deploy again

Note: This is also applicable for non maven project.

How can I tell jaxb / Maven to generate multiple schema packages?

i have solved with:

                        <removeOldOutput>false</removeOldOutput>
                        <clearOutputDir>false</clearOutputDir>
                        <forceRegenerate>true</forceRegenerate>

add this to each configuration ;)

Maven: add a folder or jar file into current classpath

From docs and example it is not clear that classpath manipulation is not allowed.

<configuration>
 <compilerArgs>
  <arg>classpath=${basedir}/lib/bad.jar</arg>
 </compilerArgs>
</configuration>

But see Java docs (also https://www.cis.upenn.edu/~bcpierce/courses/629/jdkdocs/tooldocs/solaris/javac.html)

-classpath path Specifies the path javac uses to look up classes needed to run javac or being referenced by other classes you are compiling. Overrides the default or the CLASSPATH environment variable if it is set.

Maybe it is possible to get current classpath and extend it,
see in maven, how output the classpath being used?

    <properties>
      <cpfile>cp.txt</cpfile>
    </properties>

  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-dependency-plugin</artifactId>
    <version>2.9</version>
    <executions>
      <execution>
        <id>build-classpath</id>
        <phase>generate-sources</phase>
        <goals>
          <goal>build-classpath</goal>
        </goals>
        <configuration>
          <outputFile>${cpfile}</outputFile>
        </configuration>
      </execution>
    </executions>
  </plugin>

Read file (Read a file into a Maven property)

<plugin>
  <groupId>org.codehaus.gmaven</groupId>
  <artifactId>gmaven-plugin</artifactId>
  <version>1.4</version>
  <executions>
    <execution>
      <phase>generate-resources</phase>
      <goals>
        <goal>execute</goal>
      </goals>
      <configuration>
        <source>
          def file = new File(project.properties.cpfile)
          project.properties.cp = file.getText()
        </source>
      </configuration>
    </execution>
  </executions>
</plugin>

and finally

  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.6.1</version>
    <configuration>
      <compilerArgs>
         <arg>classpath=${cp}:${basedir}/lib/bad.jar</arg>
      </compilerArgs>
    </configuration>
   </plugin>

"Faceted Project Problem (Java Version Mismatch)" error message

I encountered this issue while running an app on Java 1.6 while I have all three versions of Java 6,7,8 for different apps.I accessed the Navigator View and manually removed the unwanted facet from the facet.core.xml .Clean build and wallah!

<?xml version="1.0" encoding="UTF-8"?>

<fixed facet="jst.java"/>

<fixed facet="jst.web"/>

<installed facet="jst.web" version="2.4"/>

<installed facet="jst.java" version="6.0"/>

<installed facet="jst.utility" version="1.0"/>

Maven: How to include jars, which are not available in reps into a J2EE project?

Continue to use them as a system dependency and copy them over to target/.../WEB-INF/lib ... using the Maven dependency plugin:

http://maven.apache.org/plugins/maven-dependency-plugin/examples/copying-artifacts.html

How can I create an executable JAR with dependencies using Maven?

To create an executable JAR from command line itself just run the below command from the project path:

mvn assembly:assembly

How do I get Maven to use the correct repositories?

By default, Maven will always look in the official Maven repository, which is http://repo1.maven.org.

When Maven tries to build a project, it will look in your local repository (by default ~/.m2/repository but you can configure it by changing the <localRepository> value in your ~/.m2/settings.xml) to find any dependency, plugin or report defined in your pom.xml. If the adequate artifact is not found in your local repository, it will look in all external repositories configured, starting with the default one, http://repo1.maven.org.

You can configure Maven to avoid this default repository by setting a mirror in your settings.xml file:

<mirrors>
    <mirror>
        <id>repoMirror</id>
        <name>Our mirror for Maven repository</name>
        <url>http://the/server/</url>
        <mirrorOf>*</mirrorOf>
    </mirror>
</mirrors>

This way, instead of contacting http://repo1.maven.org, Maven will contact your entreprise repository (http://the/server in this example).

If you want to add another repository, you can define a new one in your settings.xml file:

<profiles>
    <profile>
        <activation>
            <activeByDefault>true</activeByDefault>
        </activation>
        <repositories>
            <repository>
                <id>foo.bar</id>
                <releases>
                    <enabled>true</enabled>
                </releases>
                <snapshots>
                    <enabled>true</enabled>
                </snapshots>
                <url>http://new/repository/server</url>
            </repository>
        </repositories>

You can see the complete settings.xml model here.

Concerning the clean process, you can ask Maven to run it offline. In this case, Maven will not try to reach any external repositories:

mvn -o clean 

Unable to use Intellij with a generated sources folder

With gradle, the project settings will be cleared whenever you refresh the gradle settings. Instead you need to add the following lines (or similar) in your build.gradle, I'm using kotlin so:

sourceSets {
    main {
        java {
            srcDir "${buildDir.absolutePath}/generated/source/kapt/main"
        }
    }
}

Why maven settings.xml file is not there?

settings.xml is not required (and thus not autocreated in ~/.m2 folder) unless you want to change the default settings.

Standalone maven and the maven in eclipse will use the same local repository (~/.m2 folder). This means if some artifacts/dependencies are downloaded by standalone maven, it will not be again downloaded by maven in eclipse.

Based on the version of Eclipse that you use, you may have different maven version in eclipse compared to the standalone. It should not matter in most cases.

Debugging in Maven?

I use the MAVEN_OPTS option, and find it useful to set suspend to "suspend=y" as my exec:java programs tend to be small generators which are finished before I have manage to attach a debugger.... :) With suspend on it will wait for a debugger to attach before proceding.

How do I install Maven with Yum?

For future reference and for simplicity sake for the lazy people out there that don't want much explanations but just run things and make it work asap:

1) sudo wget https://repos.fedorapeople.org/repos/dchen/apache-maven/epel-apache-maven.repo -O /etc/yum.repos.d/epel-apache-maven.repo

2) sudo sed -i s/\$releasever/6/g /etc/yum.repos.d/epel-apache-maven.repo

3) sudo yum install -y apache-maven

4) mvn --version

Hope you enjoyed this copy & paste session.

mvn clean install vs. deploy vs. release

  • mvn install will put your packaged maven project into the local repository, for local application using your project as a dependency.
  • mvn release will basically put your current code in a tag on your SCM, change your version in your projects.
  • mvn deploy will put your packaged maven project into a remote repository for sharing with other developers.

Resources :

m2e lifecycle-mapping not found

The org.eclipse.m2e:lifecycle-mapping plugin doesn't exist actually. It should be used from the <build><pluginManagement> section of your pom.xml. That way, it's not resolved by Maven but can be read by m2e.

But a more practical solution to your problem would be to install the m2e build-helper connector in eclipse. You can install it from the Window > Preferences > Maven > Discovery > Open Catalog. That way build-helper-maven-plugin:add-sources would be called in eclipse without having you to change your pom.xml.

How to update maven repository in Eclipse?

Right-click on your project and choose Maven > Update Snapshots. In addition to that you can set "update Maven projects on startup" in Window > Preferences > Maven

UPDATE: In latest versions of Eclipse: Maven > Update Project. Make sure "Force Update of Snapshots/Releases" is checked.

Maven artifact and groupId naming

Weirdness is highly subjective, I just suggest to follow the official recommendation:

Guide to naming conventions on groupId, artifactId and version

  • groupId will identify your project uniquely across all projects, so we need to enforce a naming schema. It has to follow the package name rules, what means that has to be at least as a domain name you control, and you can create as many subgroups as you want. Look at More information about package names.

    eg. org.apache.maven, org.apache.commons

    A good way to determine the granularity of the groupId is to use the project structure. That is, if the current project is a multiple module project, it should append a new identifier to the parent's groupId.

    eg. org.apache.maven, org.apache.maven.plugins, org.apache.maven.reporting

  • artifactId is the name of the jar without version. If you created it then you can choose whatever name you want with lowercase letters and no strange symbols. If it's a third party jar you have to take the name of the jar as it's distributed.

    eg. maven, commons-math

  • version if you distribute it then you can choose any typical version with numbers and dots (1.0, 1.1, 1.0.1, ...). Don't use dates as they are usually associated with SNAPSHOT (nightly) builds. If it's a third party artifact, you have to use their version number whatever it is, and as strange as it can look.

    eg. 2.0, 2.0.1, 1.3.1

MAVEN_HOME, MVN_HOME or M2_HOME

M2_HOME (and the like) is not to be used as of Maven 3.5.0. See MNG-5607 and Release Notes for details.

Maven command to determine which settings.xml file Maven is using

Your comment to cletus' (correct) answer implies that there are multiple Maven settings files involved.

Maven always uses either one or two settings files. The global settings defined in (${M2_HOME}/conf/settings.xml) is always required. The user settings file (defined in ${user.home}/.m2/settings.xml) is optional. Any settings defined in the user settings take precedence over the corresponding global settings.

You can override the location of the global and user settings from the command line, the following example will set the global settings to c:\global\settings.xml and the user settings to c:\user\settings.xml:

mvn install --settings c:\user\settings.xml 
    --global-settings c:\global\settings.xml

Currently there is no property or means to establish what user and global settings files were used from with Maven. To access these values, you would have to modify MavenCli and/or DefaultMavenSettingsBuilder to inject the file locations into the resolved Settings object.

Why does Maven have such a bad rep?

Maven is cool.


Stop listening to the alternatives, because right now, there aren't any - which aren't just toys.

Apart from the Microsoft development toolchain - it's best technology that money can't buy.

All these groups who are trying to push 'toolchain du jour' - it's just a cheap attempt to sow confusion and grab market-share.


Haters be hating.

  • SBT

Greatest misnomer in history of the earth. Can your Build pass a Turing test? Fucking ridiculous, a step 10 years back in time with it's ridiculous DSL. Uses IVY dependency management, Maven's middle sibling.

  • ANT

Great for that first project after you graduate from Shockwave development.

You understand XML, and are enthusiastic, but don't really understand build phases, restarting a project 6 months later, why Version Controlling binary artifacts is a false panacea or that someone other than oneself will one day try to work with your project.

  • MAKE

If the whole world runs in the same UNIX terminal, and speaks fluent Bash, then yeah. But why not just become a C/C++ programmer, it's much more fun than Java anyhow.

  • Ruby (Various)

Whatever. Niche, slow. Just develop Ruby then, stay away from Java development.

  • Python

People use Java where they don't trust Python (anywhere there's money involved). If your system is running Python anyway, you wont even be reading this, unless of course you want the Java money - but are stuck developing Python in some web shop.

  • Clojure (Various)

In honour of Stallman, I'll learn Lisp - but for Emacs, not so that I run it upon my VM. I feel that it cheapens the experience.

How to configure Eclipse build path to use Maven dependencies?

Right click on the project Configure > convert to Maven project

Then you can see all the Maven related Menu for you project.

Convert Existing Eclipse Project to Maven Project

It's necessary because, more or less, when we import a project from git, it's not a maven project, so the maven dependencies are not in the build path.

Here's what I have done to turn a general project to a maven project.

general project-->java project right click the project, properties->project facets, click "java". This step will turn a general project into java project.

java project --> maven project right click project, configure-->convert to maven project At this moment, maven dependencies lib are still not in the build path. project properties, build path, add library, add maven dependencies lib

And wait a few seconds, when the dependencies are loaded, the project is ready!

Best practices for copying files with Maven

Well, maven is not supposed to be good in doing fine granular tasks, it is not a scripting language like bash or ant, it is rather declarative - you say - i need a war, or an ear, and you get it. However if you need to customize how the war or ear should look like inside, you have a problem. It is just not procedural like ant, but declarative. This have some pros in the beginning, and could have a lot of cons at the end.

I guess the initial concept was to have fine plugins, that "just work" but the reality is different if you do non-standard stuff.

If you however put enough effort in your poms and few custom plugins, you'll get a much better build environment as with ant for example (depends on you project of course, but it gets more and more true for bigger projects).

Buiding Hadoop with Eclipse / Maven - Missing artifact jdk.tools:jdk.tools:jar:1.6

try :

mvn install:install-file -DgroupId=jdk.tools -DartifactId=jdk.tools -Dversion=1.6 -Dpackaging=jar -Dfile="C:\Program Files\Java\jdk\lib\tools.jar"

also check : http://maven.apache.org/guides/mini/guide-3rd-party-jars-local.html

run main class of Maven project

Although maven exec does the trick here, I found it pretty poor for a real test. While waiting for maven shell, and hoping this could help others, I finally came out to this repo mvnexec

Clone it, and symlink the script somewhere in your path. I use ~/bin/mvnexec, as I have ~/bin in my path. I think mvnexec is a good name for the script, but is up to you to change the symlink...

Launch it from the root of your project, where you can see src and target dirs.

The script search for classes with main method, offering a select to choose one (Example with mavenized JMeld project)

$ mvnexec 
 1) org.jmeld.ui.JMeldComponent
 2) org.jmeld.ui.text.FileDocument
 3) org.jmeld.JMeld
 4) org.jmeld.util.UIDefaultsPrint
 5) org.jmeld.util.PrintProperties
 6) org.jmeld.util.file.DirectoryDiff
 7) org.jmeld.util.file.VersionControlDiff
 8) org.jmeld.vc.svn.InfoCmd
 9) org.jmeld.vc.svn.DiffCmd
10) org.jmeld.vc.svn.BlameCmd
11) org.jmeld.vc.svn.LogCmd
12) org.jmeld.vc.svn.CatCmd
13) org.jmeld.vc.svn.StatusCmd
14) org.jmeld.vc.git.StatusCmd
15) org.jmeld.vc.hg.StatusCmd
16) org.jmeld.vc.bzr.StatusCmd
17) org.jmeld.Main
18) org.apache.commons.jrcs.tools.JDiff
#? 

If one is selected (typing number), you are prompt for arguments (you can avoid with mvnexec -P)

By default it compiles project every run. but you can avoid that using mvnexec -B

It allows to search only in test classes -M or --no-main, or only in main classes -T or --no-test. also has a filter by name option -f <whatever>

Hope this could save you some time, for me it does.

A simple command line to download a remote maven2 artifact to the local repository?

As of version 2.4 of the Maven Dependency Plugin, you can also define a target destination for the artifact by using the -Ddest flag. It should point to a filename (not a directory) for the destination artifact. See the parameter page for additional parameters that can be used

mvn org.apache.maven.plugins:maven-dependency-plugin:2.4:get \
    -DremoteRepositories=http://download.java.net/maven/2 \
    -Dartifact=robo-guice:robo-guice:0.4-SNAPSHOT \
    -Ddest=c:\temp\robo-guice.jar

Get Maven artifact version at runtime

To get this running in Eclipse, as well as in a Maven build, you should add the addDefaultImplementationEntries and addDefaultSpecificationEntries pom entries as described in other replies, then use the following code:

public synchronized static final String getVersion() {
    // Try to get version number from pom.xml (available in Eclipse)
    try {
        String className = getClass().getName();
        String classfileName = "/" + className.replace('.', '/') + ".class";
        URL classfileResource = getClass().getResource(classfileName);
        if (classfileResource != null) {
            Path absolutePackagePath = Paths.get(classfileResource.toURI())
                    .getParent();
            int packagePathSegments = className.length()
                    - className.replace(".", "").length();
            // Remove package segments from path, plus two more levels
            // for "target/classes", which is the standard location for
            // classes in Eclipse.
            Path path = absolutePackagePath;
            for (int i = 0, segmentsToRemove = packagePathSegments + 2;
                    i < segmentsToRemove; i++) {
                path = path.getParent();
            }
            Path pom = path.resolve("pom.xml");
            try (InputStream is = Files.newInputStream(pom)) {
                Document doc = DocumentBuilderFactory.newInstance()
                        .newDocumentBuilder().parse(is);
                doc.getDocumentElement().normalize();
                String version = (String) XPathFactory.newInstance()
                        .newXPath().compile("/project/version")
                        .evaluate(doc, XPathConstants.STRING);
                if (version != null) {
                    version = version.trim();
                    if (!version.isEmpty()) {
                        return version;
                    }
                }
            }
        }
    } catch (Exception e) {
        // Ignore
    }

    // Try to get version number from maven properties in jar's META-INF
    try (InputStream is = getClass()
        .getResourceAsStream("/META-INF/maven/" + MAVEN_PACKAGE + "/"
                + MAVEN_ARTIFACT + "/pom.properties")) {
        if (is != null) {
            Properties p = new Properties();
            p.load(is);
            String version = p.getProperty("version", "").trim();
            if (!version.isEmpty()) {
                return version;
            }
        }
    } catch (Exception e) {
        // Ignore
    }

    // Fallback to using Java API to get version from MANIFEST.MF
    String version = null;
    Package pkg = getClass().getPackage();
    if (pkg != null) {
        version = pkg.getImplementationVersion();
        if (version == null) {
            version = pkg.getSpecificationVersion();
        }
    }
    version = version == null ? "" : version.trim();
    return version.isEmpty() ? "unknown" : version;
}

If your Java build puts target classes somewhere other than "target/classes", then you may need to adjust the value of segmentsToRemove.

Exclude all transitive dependencies of a single dependency

What is your reason for excluding all transitive dependencies?

If there is a particular artifact (such as commons-logging) which you need to exclude from every dependency, the Version 99 Does Not Exist approach might help.


Update 2012: Don't use this approach. Use maven-enforcer-plugin and exclusions. Version 99 produces bogus dependencies and the Version 99 repository is offline (there are similar mirrors but you can't rely on them to stay online forever either; it's best to use only Maven Central).

Maven: how to override the dependency added by a library

I also had trouble overruling a dependency in a third party library. I used scot's approach with the exclusion but I also added the dependency with the newer version in the pom. (I used Maven 3.3.3)

So for the stAX example it would look like this:

<dependency>
  <groupId>a.group</groupId>
  <artifactId>a.artifact</artifactId>
  <version>a.version</version>
  <exclusions>
    <!--  STAX comes with Java 1.6 -->
    <exclusion>
      <artifactId>stax-api</artifactId>
      <groupId>javax.xml.stream</groupId>
    </exclusion>
    <exclusion>
      <artifactId>stax-api</artifactId>
      <groupId>stax</groupId>
    </exclusion>
  </exclusions>
<dependency>

<dependency>
    <groupId>javax.xml.stream</groupId>
    <artifactId>stax-api</artifactId>
    <version>1.0-2</version>
</dependency>

Is there anyway to exclude artifacts inherited from a parent POM?

I really needed to do this dirty thing... Here is how

I redefined those dependencies with scope test. Scope provided did not work for me.

We use spring Boot plugin to build fat jar. We have module common which defines common libraries, for example Springfox swagger-2. My super-service needs to have parent common (it does not want to do so, but company rules force!)

So my parent or commons has pom.

<dependencyManagement>

    <!- I do not need Springfox in one child but in others ->

    <dependencies>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>${swagger.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>com.google.guava</groupId>
                    <artifactId>guava</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>${swagger.version}</version>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-bean-validators</artifactId>
            <version>${swagger.version}</version>
        </dependency>

       <!- All services need them ->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>${apache.poi.version}</version>
        </dependency>
    </dependencies>
</dependencyManagement>

And my super-service pom.

<name>super-service</name>
<parent>
    <groupId>com.company</groupId>
    <artifactId>common</artifactId>
    <version>1</version>
</parent>

<dependencies>

    <!- I don't need them ->

    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-bean-validators</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-core</artifactId>
        <version>2.8.0</version>
        <scope>test</scope>
    </dependency>

    <!- Required dependencies ->

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
     <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
    </dependency>
    <dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi-ooxml</artifactId>
    </dependency>
</dependencies>

This is size of the final fat artifact

82.3 MB (86,351,753 bytes) - redefined dependency with scope test
86.1 MB (90,335,466 bytes) - redefined dependency with scope provided
86.1 MB (90,335,489 bytes) - without exclusion

Also this answer is worth mentioning - I wanted to do so, but I am lazy... https://stackoverflow.com/a/48103554/4587961

How to get a dependency tree for an artifact?

I know this post is quite old, but still, if anyone using IntelliJ any want to see dependency tree directly in IDE then they can install Maven Helper Plugin plugin.

Once installed open pom.xml and you would able to see Dependency Analyze tab like below. It also provides option to see dependency that is conflicted only and also as a tree structure.

enter image description here

How to get Maven project version to the bash command line

I noticed some spurious Downloaded: lines coming in the output that were breaking my original assignment. Here's the filter I've settled on; hope it helps!

version=$(mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | egrep -v '^\[|Downloading:' | tr -d ' \n')

EDIT

Not 100% sure why, but when running this through a post-build script in Jenkins, the output was coming out as [INFO]version, e.g. [INFO]0.3.2.

I dumped the output to a file and ran it through my first filter directly from BASH, it works fine.., so again, unsure what's going on in Jenkins land.

To get it 100% in Jenkins, I've added a follow-up sed filter; here's my latest

version=$(mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | egrep -v '^\[|Downloading:' | tr -d ' \n' | sed -E 's/\[.*\]//g')

EDIT

One last note here.. I found out tr was still resulting in things like /r/n0.3.2 (again only when running via Jenkins). Switched to awk and the problem has gone away! My final working result

mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version \
| egrep -v '^\[|Downloading:' | sed 's/[^0-9\.]//g' | awk 1 ORS=''

How to add an extra source directory for maven to compile and include in the build jar?

You can use the Build Helper Plugin, e.g:

<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>build-helper-maven-plugin</artifactId>
        <version>3.2.0</version>
        <executions>
          <execution>
            <id>add-source</id>
            <phase>generate-sources</phase>
            <goals>
              <goal>add-source</goal>
            </goals>
            <configuration>
              <sources>
                <source>some directory</source>
                ...
              </sources>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>

I want to execute shell commands from Maven's pom.xml

Solved. The problem is, executable is working in a different way in Linux. If you want to run an .sh file, you should add the exec-maven-plugin to the <plugins> section of your pom.xml file.

<plugin>
  <artifactId>exec-maven-plugin</artifactId>
  <version>3.0.0</version>
  <groupId>org.codehaus.mojo</groupId>
  <executions>
    <execution>
      <!-- Run our version calculation script -->
      <id>Renaming build artifacts</id>
      <phase>package</phase>
      <goals>
        <goal>exec</goal>
      </goals>
      <configuration>
        <executable>bash</executable>
        <commandlineArgs>handleResultJars.sh</commandlineArgs>
      </configuration>
    </execution>
  </executions>
</plugin>

Build Maven Project Without Running Unit Tests

mvn clean install -Dskiptests=true   

Now, the only difference from the answers above is that the "T" is in lower case.

SLF4J: Class path contains multiple SLF4J bindings

The error probably gives more information like this (although your jar names could be different)

SLF4J: Found binding in [jar:file:/D:/Java/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: Found binding in [jar:file:/D:/Java/repository/org/apache/logging/log4j/log4j-slf4j-impl/2.8.2/log4j-slf4j-impl-2.8.2.jar!/org/slf4j/impl/StaticLoggerBinder.class]

Noticed that the conflict comes from two jars, named logback-classic-1.2.3 and log4j-slf4j-impl-2.8.2.jar.

Run mvn dependency:tree in this project pom.xml parent folder, giving:

dependency tree conflict

Now choose the one you want to ignore (could consume a delicate endeavor I need more help on this)

I decided not to use the one imported from spring-boot-starter-data-jpa (the top dependency) through spring-boot-starter and through spring-boot-starter-logging, pom becomes:

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-logging</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>

in above pom spring-boot-starter-data-jpa would use the spring-boot-starter configured in the same file, which excludes logging (it contains logback)

No restricted globals

Try adding window before location (i.e. window.location).

Get HTML source of WebElement in Selenium WebDriver using Python

You can read the innerHTML attribute to get the source of the content of the element or outerHTML for the source with the current element.

Python:

element.get_attribute('innerHTML')

Java:

elem.getAttribute("innerHTML");

C#:

element.GetAttribute("innerHTML");

Ruby:

element.attribute("innerHTML")

JavaScript:

element.getAttribute('innerHTML');

PHP:

$element->getAttribute('innerHTML');

It was tested and worked with the ChromeDriver.

jQuery send string as POST parameters

I see that they did not understand your question.

Answer is: add "traditional" parameter to your ajax call like this:

$.ajax({
  traditional: true,
  type: "POST",
  url: url,
  data: custom,
  success: ok,
  dataType: "json"
});

And it will work with parameters PASSED AS A STRING.

get next sequence value from database using hibernate

I found the solution:

public class DefaultPostgresKeyServer
{
    private Session session;
    private Iterator<BigInteger> iter;
    private long batchSize;

    public DefaultPostgresKeyServer (Session sess, long batchFetchSize)
    {
        this.session=sess;
        batchSize = batchFetchSize;
        iter = Collections.<BigInteger>emptyList().iterator();
    }

        @SuppressWarnings("unchecked")
        public Long getNextKey()
        {
            if ( ! iter.hasNext() )
            {
                Query query = session.createSQLQuery( "SELECT nextval( 'mySchema.mySequence' ) FROM generate_series( 1, " + batchSize + " )" );

                iter = (Iterator<BigInteger>) query.list().iterator();
            }
            return iter.next().longValue() ;
        }

}

What is the difference between the kernel space and the user space?

The maximum size of address space depends on the length of the address register on the CPU.

On systems with 32-bit address registers, the maximum size of address space is 232 bytes, or 4 GiB. Similarly, on 64-bit systems, 264 bytes can be addressed.

Such address space is called virtual memory or virtual address space. It is not actually related to physical RAM size.

On Linux platforms, virtual address space is divided into kernel space and user space.

An architecture-specific constant called task size limit, or TASK_SIZE, marks the position where the split occurs:

  • the address range from 0 up to TASK_SIZE-1 is allotted to user space;

  • the remainder from TASK_SIZE up to 232-1 (or 264-1) is allotted to kernel space.

On a particular 32-bit system for example, 3 GiB could be occupied for user space and 1 GiB for kernel space.

Each application/program in a Unix-like operating system is a process; each of those has a unique identifier called Process Identifier (or simply Process ID, i.e. PID). Linux provides two mechanisms for creating a process: 1. the fork() system call, or 2. the exec() call.

A kernel thread is a lightweight process and also a program under execution. A single process may consist of several threads sharing the same data and resources but taking different paths through the program code. Linux provides a clone() system call to generate threads.

Example uses of kernel threads are: data synchronization of RAM, helping the scheduler to distribute processes among CPUs, etc.

Printing pointers in C

It's not a pointer to character char* but a pointer to array of 4 characters: char* [4]. With g++ it doesn't compile:

main.cpp: In function ‘int main(int, char**)’: main.cpp:126: error: cannot convert ‘char (*)[4]’ to ‘char**’ in initialization

Moreover, the linux man pages says:

p

The void * pointer argument is printed in hexadecimal (as if by %#x or %#lx). It shoud be pointer to void.

You can change your code to:

char* s = "asd";
char** p = &s;

printf("The value of s is: %p\n", s);
printf("The address of s is: %p\n", &s);

printf("The value of p is: %p\n", p);
printf("The address of p is: %p\n", &p);

printf("The address of s[0] is: %p\n", &s[0]);
printf("The address of s[1] is: %p\n", &s[1]);
printf("The address of s[2] is: %p\n", &s[2]);

result:

The value of s is: 0x403f00

The address of s is: 0x7fff2df9d588

The value of p is: 0x7fff2df9d588

The address of p is: 0x7fff2df9d580

The address of s[0] is: 0x403f00

The address of s[1] is: 0x403f01

The address of s[2] is: 0x403f02

Django - taking values from POST request

If you need to do something on the front end you can respond to the onsubmit event of your form. If you are just posting to admin/start you can access post variables in your view through the request object. request.POST which is a dictionary of post variables

Passing a callback function to another class

You could change your code in this way:

public delegate void CallbackHandler(string str);

public class ServerRequest
{
    public void DoRequest(string request, CallbackHandler callback)
    {
        // do stuff....
        callback("asdf");
    }
}

How to clone a Date object?

This is the cleanest approach

_x000D_
_x000D_
let dat = new Date() _x000D_
let copyOf = new Date(dat.valueOf())_x000D_
_x000D_
console.log(dat);_x000D_
console.log(copyOf);
_x000D_
_x000D_
_x000D_

How to check if input file is empty in jQuery

Here is the jQuery version of it:

if ($('#videoUploadFile').get(0).files.length === 0) {
    console.log("No files selected.");
}

How do I dynamically set the selected option of a drop-down list using jQuery, JavaScript and HTML?

SCRIPT

 <script type="text/javascript">
    $(function(){
        $("#gender").val("Male").attr("selected","selected");
    });
 </script>

HTML

<select id="gender" selected="selected">
    <option>--Select--</option>
    <option value="1">Male</option>
    <option value="2">Female</option>
</select>

Click Here More Details

What is the difference between g++ and gcc?

Although the gcc and g++ commands do very similar things, g++ is designed to be the command you'd invoke to compile a C++ program; it's intended to automatically do the right thing.

Behind the scenes, they're really the same program. As I understand, both decide whether to compile a program as C or as C++ based on the filename extension. Both are capable of linking against the C++ standard library, but only g++ does this by default. So if you have a program written in C++ that doesn't happen to need to link against the standard library, gcc will happen to do the right thing; but then, so would g++. So there's really no reason not to use g++ for general C++ development.

Use stored procedure to insert some data into a table

if you want to populate a table in SQL SERVER you can use while statement as follows:

declare @llenandoTabla INT = 0;
while @llenandoTabla < 10000
begin
insert into employeestable // Name of my table
(ID, FIRSTNAME, LASTNAME, GENDER, SALARY) // Parameters of my table
VALUES 
(555, 'isaias', 'perez', 'male', '12220') //values
set @llenandoTabla = @llenandoTabla + 1;
end

Hope it helps.

Force drop mysql bypassing foreign key constraint

Drop database exist in all versions of MySQL. But if you want to keep the table structure, here is an idea

mysqldump --no-data --add-drop-database --add-drop-table -hHOSTNAME -uUSERNAME -p > dump.sql

This is a program, not a mysql command

Then, log into mysql and

source dump.sql;

SelectSingleNode returning null for known good xml node path using XPath

just use //id instead of /id. It works fine in my code

Difference between onCreate() and onStart()?

Take a look on life cycle of Activity enter image description here

Where

***onCreate()***

Called when the activity is first created. This is where you should do all of your normal static set up: create views, bind data to lists, etc. This method also provides you with a Bundle containing the activity's previously frozen state, if there was one. Always followed by onStart().

***onStart()***

Called when the activity is becoming visible to the user. Followed by onResume() if the activity comes to the foreground, or onStop() if it becomes hidden.

And you can write your simple class to take a look when these methods call

public class TestActivity extends Activity {
    /** Called when the activity is first created. */

    private final static String TAG = "TestActivity";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Log.i(TAG, "On Create .....");
    }
    /* (non-Javadoc)
    * @see android.app.Activity#onDestroy()
    */
    @Override
    protected void onDestroy() { 
        super.onDestroy();
        Log.i(TAG, "On Destroy .....");
    }
    /* (non-Javadoc)
    * @see android.app.Activity#onPause()
    */
    @Override
    protected void onPause() { 
        super.onPause();
        Log.i(TAG, "On Pause .....");
    }

    /* (non-Javadoc)
    * @see android.app.Activity#onRestart()
    */
    @Override
    protected void onRestart() {
        super.onRestart();
        Log.i(TAG, "On Restart .....");
    }

    /* (non-Javadoc)
    * @see android.app.Activity#onResume()
    */
    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "On Resume .....");
    }

    /* (non-Javadoc)
    * @see android.app.Activity#onStart()
    */
    @Override
    protected void onStart() {
        super.onStart();
        Log.i(TAG, "On Start .....");
    }
    /* (non-Javadoc)
    * @see android.app.Activity#onStop()
    */
    @Override
    protected void onStop() {
        super.onStop();
        Log.i(TAG, "On Stop .....");
    }
}

Hope this will clear your confusion.

And take a look here for details.

Lifecycle Methods in Details is a very good example and demo application, which is a very good article to understand the life cycle.

Warning: Found conflicts between different versions of the same dependent assembly

Also had this problem - in my case it was caused by having the "Specific Version" property on a number of references set to true. Changing this to false on those references resolved the issue.

What does this symbol mean in IntelliJ? (red circle on bottom-left corner of file name, with 'J' in it)

I downloaded a project from github with .idea folder. After deleting that folder, everything was ok.

Setting session variable using javascript

A session is stored server side, you can't modify it with JavaScript. Sessions may contain sensitive data.

You can modify cookies using document.cookie.

You can easily find many examples how to modify cookies.

Python 2.7 getting user input and manipulating as string without quotations

The function input will also evaluate the data it just read as python code, which is not really what you want.

The generic approach would be to treat the user input (from sys.stdin) like any other file. Try

import sys
sys.stdin.readline()

If you want to keep it short, you can use raw_input which is the same as input but omits the evaluation.

WebSockets protocol vs HTTP

1) Why is the WebSockets protocol better?

WebSockets is better for situations that involve low-latency communication especially for low latency for client to server messages. For server to client data you can get fairly low latency using long-held connections and chunked transfer. However, this doesn't help with client to server latency which requires a new connection to be established for each client to server message.

Your 48 byte HTTP handshake is not realistic for real-world HTTP browser connections where there is often several kilobytes of data sent as part of the request (in both directions) including many headers and cookie data. Here is an example of a request/response to using Chrome:

Example request (2800 bytes including cookie data, 490 bytes without cookie data):

GET / HTTP/1.1
Host: www.cnn.com
Connection: keep-alive
Cache-Control: no-cache
Pragma: no-cache
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.17 (KHTML, like Gecko) Chrome/24.0.1312.68 Safari/537.17
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
Cookie: [[[2428 byte of cookie data]]]

Example response (355 bytes):

HTTP/1.1 200 OK
Server: nginx
Date: Wed, 13 Feb 2013 18:56:27 GMT
Content-Type: text/html
Transfer-Encoding: chunked
Connection: keep-alive
Set-Cookie: CG=US:TX:Arlington; path=/
Last-Modified: Wed, 13 Feb 2013 18:55:22 GMT
Vary: Accept-Encoding
Cache-Control: max-age=60, private
Expires: Wed, 13 Feb 2013 18:56:54 GMT
Content-Encoding: gzip

Both HTTP and WebSockets have equivalent sized initial connection handshakes, but with a WebSocket connection the initial handshake is performed once and then small messages only have 6 bytes of overhead (2 for the header and 4 for the mask value). The latency overhead is not so much from the size of the headers, but from the logic to parse/handle/store those headers. In addition, the TCP connection setup latency is probably a bigger factor than the size or processing time for each request.

2) Why was it implemented instead of updating HTTP protocol?

There are efforts to re-engineer the HTTP protocol to achieve better performance and lower latency such as SPDY, HTTP 2.0 and QUIC. This will improve the situation for normal HTTP requests, but it is likely that WebSockets and/or WebRTC DataChannel will still have lower latency for client to server data transfer than HTTP protocol (or it will be used in a mode that looks a lot like WebSockets anyways).

Update:

Here is a framework for thinking about web protocols:

  • TCP: low-level, bi-directional, full-duplex, and guaranteed order transport layer. No browser support (except via plugin/Flash).
  • HTTP 1.0: request-response transport protocol layered on TCP. The client makes one full request, the server gives one full response, and then the connection is closed. The request methods (GET, POST, HEAD) have specific transactional meaning for resources on the server.
  • HTTP 1.1: maintains the request-response nature of HTTP 1.0, but allows the connection to stay open for multiple full requests/full responses (one response per request). Still has full headers in the request and response but the connection is re-used and not closed. HTTP 1.1 also added some additional request methods (OPTIONS, PUT, DELETE, TRACE, CONNECT) which also have specific transactional meanings. However, as noted in the introduction to the HTTP 2.0 draft proposal, HTTP 1.1 pipelining is not widely deployed so this greatly limits the utility of HTTP 1.1 to solve latency between browsers and servers.
  • Long-poll: sort of a "hack" to HTTP (either 1.0 or 1.1) where the server does not respond immediately (or only responds partially with headers) to the client request. After a server response, the client immediately sends a new request (using the same connection if over HTTP 1.1).
  • HTTP streaming: a variety of techniques (multipart/chunked response) that allow the server to send more than one response to a single client request. The W3C is standardizing this as Server-Sent Events using a text/event-stream MIME type. The browser API (which is fairly similar to the WebSocket API) is called the EventSource API.
  • Comet/server push: this is an umbrella term that includes both long-poll and HTTP streaming. Comet libraries usually support multiple techniques to try and maximize cross-browser and cross-server support.
  • WebSockets: a transport layer built-on TCP that uses an HTTP friendly Upgrade handshake. Unlike TCP, which is a streaming transport, WebSockets is a message based transport: messages are delimited on the wire and are re-assembled in-full before delivery to the application. WebSocket connections are bi-directional, full-duplex and long-lived. After the initial handshake request/response, there is no transactional semantics and there is very little per message overhead. The client and server may send messages at any time and must handle message receipt asynchronously.
  • SPDY: a Google initiated proposal to extend HTTP using a more efficient wire protocol but maintaining all HTTP semantics (request/response, cookies, encoding). SPDY introduces a new framing format (with length-prefixed frames) and specifies a way to layering HTTP request/response pairs onto the new framing layer. Headers can be compressed and new headers can be sent after the connection has been established. There are real world implementations of SPDY in browsers and servers.
  • HTTP 2.0: has similar goals to SPDY: reduce HTTP latency and overhead while preserving HTTP semantics. The current draft is derived from SPDY and defines an upgrade handshake and data framing that is very similar the the WebSocket standard for handshake and framing. An alternate HTTP 2.0 draft proposal (httpbis-speed-mobility) actually uses WebSockets for the transport layer and adds the SPDY multiplexing and HTTP mapping as an WebSocket extension (WebSocket extensions are negotiated during the handshake).
  • WebRTC/CU-WebRTC: proposals to allow peer-to-peer connectivity between browsers. This may enable lower average and maximum latency communication because as the underlying transport is SDP/datagram rather than TCP. This allows out-of-order delivery of packets/messages which avoids the TCP issue of latency spikes caused by dropped packets which delay delivery of all subsequent packets (to guarantee in-order delivery).
  • QUIC: is an experimental protocol aimed at reducing web latency over that of TCP. On the surface, QUIC is very similar to TCP+TLS+SPDY implemented on UDP. QUIC provides multiplexing and flow control equivalent to HTTP/2, security equivalent to TLS, and connection semantics, reliability, and congestion control equivalentto TCP. Because TCP is implemented in operating system kernels, and middlebox firmware, making significant changes to TCP is next to impossible. However, since QUIC is built on top of UDP, it suffers from no such limitations. QUIC is designed and optimised for HTTP/2 semantics.

References:

JavaScript set object key by variable

In ES6, you can do like this.

var key = "name";
var person = {[key]:"John"}; // same as var person = {"name" : "John"}
console.log(person); // should print  Object { name="John"}

_x000D_
_x000D_
    var key = "name";_x000D_
    var person = {[key]:"John"};_x000D_
    console.log(person); // should print  Object { name="John"}
_x000D_
_x000D_
_x000D_

Its called Computed Property Names, its implemented using bracket notation( square brackets) []

Example: { [variableName] : someValue }

Starting with ECMAScript 2015, the object initializer syntax also supports computed property names. That allows you to put an expression in brackets [], that will be computed and used as the property name.

For ES5, try something like this

var yourObject = {};

yourObject[yourKey] = "yourValue";

console.log(yourObject );

example:

var person = {};
var key = "name";

person[key] /* this is same as person.name */ = "John";

console.log(person); // should print  Object { name="John"}

_x000D_
_x000D_
    var person = {};_x000D_
    var key = "name";_x000D_
    _x000D_
    person[key] /* this is same as person.name */ = "John";_x000D_
    _x000D_
    console.log(person); // should print  Object { name="John"}
_x000D_
_x000D_
_x000D_

Best way to get identity of inserted row?

After Your Insert Statement you need to add this. And Make sure about the table name where data is inserting.You will get current row no where row affected just now by your insert statement.

IDENT_CURRENT('tableName')

How to efficiently count the number of keys/properties of an object in JavaScript?

From: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty

Object.defineProperty(obj, prop, descriptor)

You can either add it to all your objects:

Object.defineProperty(Object.prototype, "length", {
    enumerable: false,
    get: function() {
        return Object.keys(this).length;
    }
});

Or a single object:

var myObj = {};
Object.defineProperty(myObj, "length", {
    enumerable: false,
    get: function() {
        return Object.keys(this).length;
    }
});

Example:

var myObj = {};
myObj.name  = "John Doe";
myObj.email = "[email protected]";
myObj.length; //output: 2

Added that way, it won't be displayed in for..in loops:

for(var i in myObj) {
     console.log(i + ":" + myObj[i]);
}

Output:

name:John Doe
email:[email protected]

Note: it does not work in < IE9 browsers.

Using setDate in PreparedStatement

tl;dr

With JDBC 4.2 or later and java 8 or later:

myPreparedStatement.setObject( … , myLocalDate  )

…and…

myResultSet.getObject( … , LocalDate.class )

Details

The Answer by Vargas is good about mentioning java.time types but refers only to converting to java.sql.Date. No need to convert if your driver is updated.

java.time

The java.time framework is built into Java 8 and later. These classes supplant the old troublesome date-time classes such as java.util.Date, .Calendar, & java.text.SimpleDateFormat. The Joda-Time team also advises migration to java.time.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations.

Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport and further adapted to Android in ThreeTenABP.

LocalDate

In java.time, the java.time.LocalDate class represents a date-only value without time-of-day and without time zone.

If using a JDBC driver compliant with JDBC 4.2 or later spec, no need to use the old java.sql.Date class. You can pass/fetch LocalDate objects directly to/from your database via PreparedStatement::setObject and ResultSet::getObject.

LocalDate localDate = LocalDate.now( ZoneId.of( "America/Montreal" ) );
myPreparedStatement.setObject( 1 , localDate  );

…and…

LocalDate localDate = myResultSet.getObject( 1 , LocalDate.class );

Before JDBC 4.2, convert

If your driver cannot handle the java.time types directly, fall back to converting to java.sql types. But minimize their use, with your business logic using only java.time types.

New methods have been added to the old classes for conversion to/from java.time types. For java.sql.Date see the valueOf and toLocalDate methods.

java.sql.Date sqlDate = java.sql.Date.valueOf( localDate );

…and…

LocalDate localDate = sqlDate.toLocalDate();

Placeholder value

Be wary of using 0000-00-00 as a placeholder value as shown in your Question’s code. Not all databases and other software can handle going back that far in time. I suggest using something like the commonly-used Unix/Posix epoch reference date of 1970, 1970-01-01.

LocalDate EPOCH_DATE = LocalDate.ofEpochDay( 0 ); // 1970-01-01 is day 0 in Epoch counting.

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

Where to obtain the java.time classes?

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

What is the default boolean value in C#?

The default value for bool is false. See this table for a great reference on default values. The only reason it would not be false when you check it is if you initialize/set it to true.

Get human readable version of file size?

The HumanFriendly project helps with this.

import humanfriendly
humanfriendly.format_size(1024)

The above code will give 1KB as answer.
Examples can be found here.

Ruby 'require' error: cannot load such file

require loads a file from the $LOAD_PATH. If you want to require a file relative to the currently executing file instead of from the $LOAD_PATH, use require_relative.

How can I make sticky headers in RecyclerView? (Without external lib)

you can get sticky header functionality by copying these 2 files into your project. i had no issues with this implementation:

  • can interact with the sticy header (tap/long press/swipe)
  • the sticky header hides and reveals itself properly...even if each view holder has a different height (some other answers here don't handle that properly, causing the wrong headers to show, or the headers to jump up and down)

see an example of the 2 files being used in this small github project i whipped up

How to get instance variables in Python?

Sometimes you want to filter the list based on public/private vars. E.g.

def pub_vars(self):
    """Gives the variable names of our instance we want to expose
    """
    return [k for k in vars(self) if not k.startswith('_')]

Get div to take up 100% body height, minus fixed-height header and footer

You can take advatange of the css property Box Sizing.

#content { 
    height: 100%;
    -webkit-box-sizing: border-box; /* Safari/Chrome, other WebKit */
    -moz-box-sizing: border-box;    /* Firefox, other Gecko */
    box-sizing: border-box;         /* Opera/IE 8+ */
    padding-top: 50px;
    margin-top: -50px;
    padding-bottom: 50px;
    margin-bottom: -50px;
}

See the JsFiddle.

Pass table as parameter into sql server UDF

you can do something like this

/* CREATE USER DEFINED TABLE TYPE */

CREATE TYPE StateMaster AS TABLE
(
 StateCode VARCHAR(2),
 StateDescp VARCHAR(250)
)
GO

/*CREATE FUNCTION WHICH TAKES TABLE AS A PARAMETER */

CREATE FUNCTION TableValuedParameterExample(@TmpTable StateMaster READONLY)
RETURNS  VARCHAR(250)
AS
BEGIN
 DECLARE @StateDescp VARCHAR(250)
 SELECT @StateDescp = StateDescp FROM @TmpTable
 RETURN @StateDescp
END
GO

/*CREATE STORED PROCEDURE WHICH TAKES TABLE AS A PARAMETER */

CREATE PROCEDURE TableValuedParameterExample_SP
(
@TmpTable StateMaster READONLY
)
AS
BEGIN
 INSERT INTO StateMst 
  SELECT * FROM @TmpTable
END
GO


BEGIN
/* DECLARE VARIABLE OF TABLE USER DEFINED TYPE */
DECLARE @MyTable StateMaster

/* INSERT DATA INTO TABLE TYPE */
INSERT INTO @MyTable VALUES('11','AndhraPradesh')
INSERT INTO @MyTable VALUES('12','Assam')

/* EXECUTE STORED PROCEDURE */
EXEC TableValuedParameterExample_SP @MyTable
GO

For more details check this link: http://sailajareddy-technical.blogspot.in/2012/09/passing-table-valued-parameter-to.html

Import pandas dataframe column as string not int

This probably isn't the most elegant way to do it, but it gets the job done.

In[1]: import numpy as np

In[2]: import pandas as pd

In[3]: df = pd.DataFrame(np.genfromtxt('/Users/spencerlyon2/Desktop/test.csv', dtype=str)[1:], columns=['ID'])

In[4]: df
Out[4]: 
                       ID
0  00013007854817840016671868
1  00013007854817840016749251
2  00013007854817840016754630
3  00013007854817840016781876
4  00013007854817840017028824
5  00013007854817840017963235
6  00013007854817840018860166

Just replace '/Users/spencerlyon2/Desktop/test.csv' with the path to your file

How to import local packages in go?

Import paths are relative to your $GOPATH and $GOROOT environment variables. For example, with the following $GOPATH:

GOPATH=/home/me/go

Packages located in /home/me/go/src/lib/common and /home/me/go/src/lib/routers are imported respectively as:

import (
    "lib/common"
    "lib/routers"
)

Submitting form and pass data to controller method of type FileStreamResult

You seem to be specifying the form to use a HTTP 'GET' request using FormMethod.Get. This will not work unless you tell it to do a post as that is what you seem to want the ActionResult to do. This will probably work by changing FormMethod.Get to FormMethod.Post.

As well as this you may also want to think about how Get and Post requests work and how these interact with the Model.

httpd Server not started: (13)Permission denied: make_sock: could not bind to address [::]:88

I had similar error while trying to start httpd service for openstack train installation in RHEL 7.5 too.

-- Unit httpd.service has begun starting up.
Jan 31 10:11:16 controller httpd[1631]: (13)Permission denied: AH00072: make_sock: could not bind to address 10.0.0.11:5000
Jan 31 10:11:16 controller httpd[1631]: no listening sockets available, shutting down
Jan 31 10:11:16 controller httpd[1631]: AH00015: Unable to open logs
Jan 31 10:11:16 controller systemd[1]: httpd.service: main process exited, code=exited, status=1/FAILURE
Jan 31 10:11:16 controller kill[1632]: kill: cannot find process ""
Jan 31 10:11:16 controller systemd[1]: httpd.service: control process exited, code=exited status=1
Jan 31 10:11:16 controller systemd[1]: Failed to start The Apache HTTP Server.
-- Subject: Unit httpd.service has failed

Solution: It got resolved by disabling SElinux.

How to solve 'Redirect has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header'?

Ask the person maintaining the server at http://172.16.1.157:8002/ to add your hostname to Access-Control-Allow-Origin hosts, the server should return a header similar to the following with the response-

Access-Control-Allow-Origin: yourhostname:port

Equation for testing if a point is inside a circle

In general, x and y must satisfy (x - center_x)^2 + (y - center_y)^2 < radius^2.

Please note that points that satisfy the above equation with < replaced by == are considered the points on the circle, and the points that satisfy the above equation with < replaced by > are considered the outside the circle.

SQL Server Escape an Underscore

This worked for me, just use the escape '%\_%'

Is there a "null coalescing" operator in JavaScript?

Logical nullish assignment, 2020+ solution

A new operator is currently being added to the browsers, ??=. This combines the null coalescing operator ?? with the assignment operator =.

NOTE: This is not common in public browser versions yet. Will update as availability changes.

??= checks if the variable is undefined or null, short-circuiting if already defined. If not, the right-side value is assigned to the variable.

Basic Examples

let a          // undefined
let b = null
let c = false

a ??= true  // true
b ??= true  // true
c ??= true  // false

Object/Array Examples

let x = ["foo"]
let y = { foo: "fizz" }

x[0] ??= "bar"  // "foo"
x[1] ??= "bar"  // "bar"

y.foo ??= "buzz"  // "fizz"
y.bar ??= "buzz"  // "buzz"

x  // Array [ "foo", "bar" ]
y  // Object { foo: "fizz", bar: "buzz" }

Browser Support Sept 2020 - 3.7%

Mozilla Documentation

SQL Server SELECT INTO @variable?

you can do this:

SELECT 
    CustomerId, 
    FirstName, 
    LastName, 
    Email
INTO #tempCustomer 
FROM 
    Customer
WHERE 
    CustomerId = @CustomerId

then later

SELECT CustomerId FROM #tempCustomer

you doesn't need to declare the structure of #tempCustomer

How does ifstream's eof() work?

The EOF flag is only set after a read operation attempts to read past the end of the file. get() is returning the symbolic constant traits::eof() (which just happens to equal -1) because it reached the end of the file and could not read any more data, and only at that point will eof() be true. If you want to check for this condition, you can do something like the following:

int ch;
while ((ch = inf.get()) != EOF) {
    std::cout << static_cast<char>(ch) << "\n";
}

Difference between "while" loop and "do while" loop

While:

  1. entry control loop

  2. condition is checked before loop execution

  3. never execute loop if condition is false

  4. there is no semicolon at the end of while statement

Do-while:

  1. exit control loop

  2. condition is checked at the end of loop

  3. executes false condition at least once since condition is checked later

  4. there is semicolon at the end of while statement.

Assert a function/method was not called using Mock

This should work for your case;

assert not my_var.called, 'method should not have been called'

Sample;

>>> mock=Mock()
>>> mock.a()
<Mock name='mock.a()' id='4349129872'>
>>> assert not mock.b.called, 'b was called and should not have been'
>>> assert not mock.a.called, 'a was called and should not have been'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AssertionError: a was called and should not have been

Right click to select a row in a Datagridview and show a menu to delete it

All the answers posed in to this question are based on a mouse click event. You can also assign a ContenxtMenuStrip to your DataGridview and check if there is a row selected when the user RightMouseButtons on the DataGridView and decide whether you want to view the ContenxtMenuStrip or not. You can do so by setting the CancelEventArgs.Cancel value in the the Opening event of the ContextMenuStrip

    private void MyContextMenuStrip_Opening(object sender, CancelEventArgs e)
    {
        //Only show ContextMenuStrip when there is 1 row selected.
        if (MyDataGridView.SelectedRows.Count != 1) e.Cancel = true;
    }

But if you have several context menu strips, with each containing different options, depending on the selection, I would go for a mouse-click-approach myself as well.

Prevent onmouseout when hovering child element of the parent absolute div WITHOUT jQuery

simply we can check e.relatedTarget has child class and if true return the function.

    if ($(e.relatedTarget).hasClass("ctrl-btn")){
        return;
    }

this is code worked for me, i used for html5 video play,pause button toggle hover video element

element.on("mouseover mouseout", function(e) {

    if(e.type === "mouseout"){

        if ($(e.relatedTarget).hasClass("child-class")){
            return;
        }

    }

});

iOS detect if user is on an iPad

I found that some solution didn't work for me in the Simulator within Xcode. Instead, this works:

ObjC

NSString *deviceModel = (NSString*)[UIDevice currentDevice].model;

if ([[deviceModel substringWithRange:NSMakeRange(0, 4)] isEqualToString:@"iPad"]) {
    DebugLog(@"iPad");
} else {
    DebugLog(@"iPhone or iPod Touch");
}

Swift

if UIDevice.current.model.hasPrefix("iPad") {
    print("iPad")
} else {
    print("iPhone or iPod Touch")
}

Also in the 'Other Examples' in Xcode the device model comes back as 'iPad Simulator' so the above tweak should sort that out.

Java: getMinutes and getHours

One more way of getting minutes and hours is by using SimpleDateFormat.

SimpleDateFormat formatMinutes = new SimpleDateFormat("mm")
String getMinutes = formatMinutes.format(new Date())

SimpleDateFormat formatHours = new SimpleDateFormat("HH")
String getHours = formatHours.format(new Date())

Evaluate a string with a switch in C++

what about just have the option number:

#include <iostream>
#include <string>
using namespace std;

int main()
{
    string s;
    int op;

    cin >> s >> op;
    switch (op) {
    case 1: break;
    case 2: break;
    default:
    }

    return 0;
}  

Read remote file with node.js (http.get)

http.get(options).on('response', function (response) {
    var body = '';
    var i = 0;
    response.on('data', function (chunk) {
        i++;
        body += chunk;
        console.log('BODY Part: ' + i);
    });
    response.on('end', function () {

        console.log(body);
        console.log('Finished');
    });
});

Changes to this, which works. Any comments?

Git: "please tell me who you are" error

IMHO, the proper way to resolve this error is to configure your global git config file.

To do that run the following command: git config --global -e

An editor will appear where you can insert your default git configurations.

Here're are a few:

[user]
    name = your_username
    email = [email protected] 
[alias]
    # BASIC
    st = status
    ci = commit
    br = branch
    co = checkout
    df = diff

For more details, see Customizing Git - Git Configuration

When you see a command like, git config ...

$ git config --global core.whitespace \
    trailing-space,space-before-tab,indent-with-non-tab

... you can put that into your global git config file as:

[core]
   whitespace = space-before-tab,-indent-with-non-tab,trailing-space

For one off configurations, you can use something like git config --global user.name 'your_username'

If you don't set your git configurations globally, you'll need to do so for each and every git repo you work with locally.

The user.name and user.email settings tell git who you are, so subsequent git commit commands will not complain, *** Please tell me who you are.

Many times, the commands git suggests you run are not what you should run. This time, the suggested commands are not bad:

$ git commit -m 'first commit'

*** Please tell me who you are.

Run

  git config --global user.email "[email protected]"
  git config --global user.name "Your Name"

Tip: Until I got very familiar with git, making a backup of my project file--before running the suggested git commands and exploring things I thought would work--saved my bacon on more than a few occasions.

Regular expression for number with length of 4, 5 or 6

If the language you use accepts {}, you can use [0-9]{4,6}.

If not, you'll have to use [0-9][0-9][0-9][0-9][0-9]?[0-9]?.

correct way to use super (argument passing)

Sometimes two classes may have some parameter names in common. In that case, you can't pop the key-value pairs off of **kwargs or remove them from *args. Instead, you can define a Base class which unlike object, absorbs/ignores arguments:

class Base(object):
    def __init__(self, *args, **kwargs): pass

class A(Base):
    def __init__(self, *args, **kwargs):
        print "A"
        super(A, self).__init__(*args, **kwargs)

class B(Base):
    def __init__(self, *args, **kwargs):
        print "B"
        super(B, self).__init__(*args, **kwargs)

class C(A):
    def __init__(self, arg, *args, **kwargs):
        print "C","arg=",arg
        super(C, self).__init__(arg, *args, **kwargs)

class D(B):
    def __init__(self, arg, *args, **kwargs):
        print "D", "arg=",arg
        super(D, self).__init__(arg, *args, **kwargs)

class E(C,D):
    def __init__(self, arg, *args, **kwargs):
        print "E", "arg=",arg
        super(E, self).__init__(arg, *args, **kwargs)

print "MRO:", [x.__name__ for x in E.__mro__]
E(10)

yields

MRO: ['E', 'C', 'A', 'D', 'B', 'Base', 'object']
E arg= 10
C arg= 10
A
D arg= 10
B

Note that for this to work, Base must be the penultimate class in the MRO.

cordova run with ios error .. Error code 65 for command: xcodebuild with args:

How to do what @connor said:

iOS

  • Open platforms/ios on XCode
  • Find & Replace io.ionic.starter in all files for a unique identifier
  • Click the project to open settings
  • Signing > Select a team
  • Go to your device Settings > General > DeviceManagement
    • Trust your account/team
  • ionic cordova run ios --device --livereload

Custom thread pool in Java 8 parallel stream

I tried the custom ForkJoinPool as follows to adjust the pool size:

private static Set<String> ThreadNameSet = new HashSet<>();
private static Callable<Long> getSum() {
    List<Long> aList = LongStream.rangeClosed(0, 10_000_000).boxed().collect(Collectors.toList());
    return () -> aList.parallelStream()
            .peek((i) -> {
                String threadName = Thread.currentThread().getName();
                ThreadNameSet.add(threadName);
            })
            .reduce(0L, Long::sum);
}

private static void testForkJoinPool() {
    final int parallelism = 10;

    ForkJoinPool forkJoinPool = null;
    Long result = 0L;
    try {
        forkJoinPool = new ForkJoinPool(parallelism);
        result = forkJoinPool.submit(getSum()).get(); //this makes it an overall blocking call

    } catch (InterruptedException | ExecutionException e) {
        e.printStackTrace();
    } finally {
        if (forkJoinPool != null) {
            forkJoinPool.shutdown(); //always remember to shutdown the pool
        }
    }
    out.println(result);
    out.println(ThreadNameSet);
}

Here is the output saying the pool is using more threads than the default 4.

50000005000000
[ForkJoinPool-1-worker-8, ForkJoinPool-1-worker-9, ForkJoinPool-1-worker-6, ForkJoinPool-1-worker-11, ForkJoinPool-1-worker-10, ForkJoinPool-1-worker-1, ForkJoinPool-1-worker-15, ForkJoinPool-1-worker-13, ForkJoinPool-1-worker-4, ForkJoinPool-1-worker-2]

But actually there is a weirdo, when I tried to achieve the same result using ThreadPoolExecutor as follows:

BlockingDeque blockingDeque = new LinkedBlockingDeque(1000);
ThreadPoolExecutor fixedSizePool = new ThreadPoolExecutor(10, 20, 60, TimeUnit.SECONDS, blockingDeque, new MyThreadFactory("my-thread"));

but I failed.

It will only start the parallelStream in a new thread and then everything else is just the same, which again proves that the parallelStream will use the ForkJoinPool to start its child threads.

add onclick function to a submit button

  1. Create a hidden button with id="hiddenBtn" and type="submit" that do the submit
  2. Change current button to type="button"
  3. set onclick of the current button call a function look like below:

    function foo() { // do something before submit ... // trigger click event of the hidden button $('#hinddenBtn').trigger("click"); }

Sort an ArrayList based on an object field

You can use the Bean Comparator to sort on any property in your custom class.

Java 8 forEach with index

It works with params if you capture an array with one element, that holds the current index.

int[] idx = { 0 };
params.forEach(e -> query.bind(idx[0]++, e));

The above code assumes, that the method forEach iterates through the elements in encounter order. The interface Iterable specifies this behaviour for all classes unless otherwise documented. Apparently it works for all implementations of Iterable from the standard library, and changing this behaviour in the future would break backward-compatibility.

If you are working with Streams instead of Collections/Iterables, you should use forEachOrdered, because forEach can be executed concurrently and the elements can occur in different order. The following code works for both sequential and parallel streams:

int[] idx = { 0 };
params.stream().forEachOrdered(e -> query.bind(idx[0]++, e));

Flatten nested dictionaries, compressing keys

I tried some of the solutions on this page - though not all - but those I tried failed to handle the nested list of dict.

Consider a dict like this:

d = {
        'owner': {
            'name': {'first_name': 'Steven', 'last_name': 'Smith'},
            'lottery_nums': [1, 2, 3, 'four', '11', None],
            'address': {},
            'tuple': (1, 2, 'three'),
            'tuple_with_dict': (1, 2, 'three', {'is_valid': False}),
            'set': {1, 2, 3, 4, 'five'},
            'children': [
                {'name': {'first_name': 'Jessica',
                          'last_name': 'Smith', },
                 'children': []
                 },
                {'name': {'first_name': 'George',
                          'last_name': 'Smith'},
                 'children': []
                 }
            ]
        }
    }

Here's my makeshift solution:

def flatten_dict(input_node: dict, key_: str = '', output_dict: dict = {}):
    if isinstance(input_node, dict):
        for key, val in input_node.items():
            new_key = f"{key_}.{key}" if key_ else f"{key}"
            flatten_dict(val, new_key, output_dict)
    elif isinstance(input_node, list):
        for idx, item in enumerate(input_node):
            flatten_dict(item, f"{key_}.{idx}", output_dict)
    else:
        output_dict[key_] = input_node
    return output_dict

which produces:

{
  owner.name.first_name: Steven,
  owner.name.last_name: Smith,
  owner.lottery_nums.0: 1,
  owner.lottery_nums.1: 2,
  owner.lottery_nums.2: 3,
  owner.lottery_nums.3: four,
  owner.lottery_nums.4: 11,
  owner.lottery_nums.5: None,
  owner.tuple: (1, 2, 'three'),
  owner.tuple_with_dict: (1, 2, 'three', {'is_valid': False}),
  owner.set: {1, 2, 3, 4, 'five'},
  owner.children.0.name.first_name: Jessica,
  owner.children.0.name.last_name: Smith,
  owner.children.1.name.first_name: George,
  owner.children.1.name.last_name: Smith,
}

A makeshift solution and it's not perfect.
NOTE:

  • it doesn't keep empty dicts such as the address: {} k/v pair.

  • it won't flatten dicts in nested tuples - though it would be easy to add using the fact that python tuples act similar to lists.

How can I write a byte array to a file in Java?

As of Java 1.7, there's a new way: java.nio.file.Files.write

import java.nio.file.Files;
import java.nio.file.Paths;

KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128);
SecretKey key = kgen.generateKey();
byte[] encoded = key.getEncoded();
Files.write(Paths.get("target-file"), encoded);

Java 1.7 also resolves the embarrassment that Kevin describes: reading a file is now:

byte[] data = Files.readAllBytes(Paths.get("source-file"));

Get Mouse Position

If you're using SWT, you might want to look at adding a MouseMoveListener as explained here.

Get index of a key in json

You don't need a numerical index for an object key, but many others have told you that.

Here's the actual answer:

var json = { "key1" : "watevr1", "key2" : "watevr2", "key3" : "watevr3" };

console.log( getObjectKeyIndex(json, 'key2') ); 
// Returns int(1) (or null if the key doesn't exist)

function getObjectKeyIndex(obj, keyToFind) {
    var i = 0, key;

    for (key in obj) {
        if (key == keyToFind) {
            return i;
        }

        i++;
    }

    return null;
}

Though you're PROBABLY just searching for the same loop that I've used in this function, so you can go through the object:

for (var key in json) {
    console.log(key + ' is ' + json[key]);
}

Which will output

key1 is watevr1
key2 is watevr2
key3 is watevr3

Selecting data from two different servers in SQL Server

Simplified solution for adding linked servers

First server

EXEC sp_addlinkedserver @server='ip,port\instancename'

Second Login

EXEC sp_addlinkedsrvlogin 'ip,port\instancename', 'false', NULL, 'remote_db_loginname', 'remote_db_pass'

Execute queries from linked to local db

INSERT INTO Tbl (Col1, Col2, Col3)
SELECT Col1, Col2, Col3
FROM [ip,port\instancename].[linkedDBName].[linkedTblSchema].[linkedTblName]

Completely Remove MySQL Ubuntu 14.04 LTS

I just had this same issue. It turns out for me, mysql was already installed and working. I just didn't know how to check.

$ ps aux | grep mysql

This will show you if mysql is already running. If it is it should return something like this:

mysql    24294  0.1  1.3 550012 52784 ?        Ssl  15:16   0:06        /usr/sbin/mysqld
gwang    27451  0.0  0.0  15940   924 pts/3    S+   16:34   0:00 grep --color=auto mysql

Using CSS :before and :after pseudo-elements with inline CSS?

If you have control over the HTML then you could add a real element instead of a pseudo one. :before and :after pseudo elements are rendered right after the open tag or right before the close tag. The inline equivalent for this css

td { text-align: justify; }
td:after { content: ""; display: inline-block; width: 100%; }

Would be something like this:

<table>
<tr>
<td style="text-align: justify;">
TD Content
<span class="inline_td_after" style="display: inline-block; width: 100%;"></span>
</td>
</tr>
</table>

Keep in mind; Your "real" before and after elements and anything with inline css will greatly increase the size of your pages and ignore page load optimizations that external css and pseudo elements make possible.

Facebook share button and custom text

We use something like this [use in one line]:

<a title="send to Facebook" 
  href="http://www.facebook.com/sharer.php?s=100&p[title]=YOUR_TITLE&p[summary]=YOUR_SUMMARY&p[url]=YOUR_URL&p[images][0]=YOUR_IMAGE_TO_SHARE_OBJECT"
  target="_blank">
  <span>
    <img width="14" height="14" src="'icons/fb.gif" alt="Facebook" /> Facebook 
  </span>
</a>

Adding header for HttpURLConnection

Your code is fine.You can also use the same thing in this way.

public static String getResponseFromJsonURL(String url) {
    String jsonResponse = null;
    if (CommonUtility.isNotEmpty(url)) {
        try {
            /************** For getting response from HTTP URL start ***************/
            URL object = new URL(url);

            HttpURLConnection connection = (HttpURLConnection) object
                    .openConnection();
            // int timeOut = connection.getReadTimeout();
            connection.setReadTimeout(60 * 1000);
            connection.setConnectTimeout(60 * 1000);
            String authorization="xyz:xyz$123";
            String encodedAuth="Basic "+Base64.encode(authorization.getBytes());
            connection.setRequestProperty("Authorization", encodedAuth);
            int responseCode = connection.getResponseCode();
            //String responseMsg = connection.getResponseMessage();

            if (responseCode == 200) {
                InputStream inputStr = connection.getInputStream();
                String encoding = connection.getContentEncoding() == null ? "UTF-8"
                        : connection.getContentEncoding();
                jsonResponse = IOUtils.toString(inputStr, encoding);
                /************** For getting response from HTTP URL end ***************/

            }
        } catch (Exception e) {
            e.printStackTrace();

        }
    }
    return jsonResponse;
}

Its Return response code 200 if authorizationis success

PHP - Copy image to my server direct from URL

This SO thread will solve your problem. Solution in short:

$url = 'http://www.google.co.in/intl/en_com/images/srpr/logo1w.png';
$img = '/my/folder/my_image.gif';
file_put_contents($img, file_get_contents($url));

Convert normal date to unix timestamp

var datestr = '2012.08.10';
var timestamp = (new Date(datestr.split(".").join("-")).getTime())/1000;

Setting Windows PowerShell environment variables

If, some time during a PowerShell session, you need to append to the PATH environment variable temporarily, you can do it this way:

$env:Path += ";C:\Program Files\GnuWin32\bin"

Javascript Get Element by Id and set the value

Coming across this question, no answer brought up the possibility of using .setAttribute() in addition to .value()

document.getElementById('some-input').value="1337";
document.getElementById('some-input').setAttribute("value", "1337");

Though unlikely helpful for the original questioner, this addendum actually changes the content of the value in the pages source, which in turn makes the value update form.reset()-proof.

I hope this may help others.

(Or me in half a year when I've forgotten about js quirks...)

How to get the HTML for a DOM element in javascript

Expanding on jldupont's answer, you could create a wrapping element on the fly:

var target = document.getElementById('myElement');
var wrap = document.createElement('div');
wrap.appendChild(target.cloneNode(true));
alert(wrap.innerHTML);

I am cloning the element to avoid having to remove and reinsert the element in the actual document. This might be expensive if the element you wish to print has a very large tree below it, though.

git with IntelliJ IDEA: Could not read from remote repository

I solved this issue by removing the password for the ssh key in PuTTY.

Reset C int array to zero : the fastest way?

memset (from <string.h>) is probably the fastest standard way, since it's usually a routine written directly in assembly and optimized by hand.

memset(myarray, 0, sizeof(myarray)); // for automatically-allocated arrays
memset(myarray, 0, N*sizeof(*myarray)); // for heap-allocated arrays, where N is the number of elements

By the way, in C++ the idiomatic way would be to use std::fill (from <algorithm>):

std::fill(myarray, myarray+N, 0);

which may be optimized automatically into a memset; I'm quite sure that it will work as fast as memset for ints, while it may perform slightly worse for smaller types if the optimizer isn't smart enough. Still, when in doubt, profile.

Differences between Ant and Maven

Maven also houses a large repository of commonly used open source projects. During the build Maven can download these dependencies for you (as well as your dependencies dependencies :)) to make this part of building a project a little more manageable.

How to make an inline-block element fill the remainder of the line?

See: http://jsfiddle.net/qx32C/36/

_x000D_
_x000D_
.lineContainer {_x000D_
    overflow: hidden; /* clear the float */_x000D_
    border: 1px solid #000_x000D_
}_x000D_
.lineContainer div {_x000D_
    height: 20px_x000D_
} _x000D_
.left {_x000D_
    width: 100px;_x000D_
    float: left;_x000D_
    border-right: 1px solid #000_x000D_
}_x000D_
.right {_x000D_
    overflow: hidden;_x000D_
    background: #ccc_x000D_
}
_x000D_
<div class="lineContainer">_x000D_
    <div class="left">left</div>_x000D_
    <div class="right">right</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_


Why did I replace margin-left: 100px with overflow: hidden on .right?

EDIT: Here are two mirrors for the above (dead) link:

Why can't I initialize non-const static member or static array in class?

Why I can't initialize static data members in class?

The C++ standard allows only static constant integral or enumeration types to be initialized inside the class. This is the reason a is allowed to be initialized while others are not.

Reference:
C++03 9.4.2 Static data members
§4

If a static data member is of const integral or const enumeration type, its declaration in the class definition can specify a constant-initializer which shall be an integral constant expression (5.19). In that case, the member can appear in integral constant expressions. The member shall still be defined in a namespace scope if it is used in the program and the namespace scope definition shall not contain an initializer.

What are integral types?

C++03 3.9.1 Fundamental types
§7

Types bool, char, wchar_t, and the signed and unsigned integer types are collectively called integral types.43) A synonym for integral type is integer type.

Footnote:

43) Therefore, enumerations (7.2) are not integral; however, enumerations can be promoted to int, unsigned int, long, or unsigned long, as specified in 4.5.

Workaround:

You could use the enum trick to initialize an array inside your class definition.

class A 
{
    static const int a = 3;
    enum { arrsize = 2 };

    static const int c[arrsize] = { 1, 2 };

};

Why does the Standard does not allow this?

Bjarne explains this aptly here:

A class is typically declared in a header file and a header file is typically included into many translation units. However, to avoid complicated linker rules, C++ requires that every object has a unique definition. That rule would be broken if C++ allowed in-class definition of entities that needed to be stored in memory as objects.

Why are only static const integral types & enums allowed In-class Initialization?

The answer is hidden in Bjarne's quote read it closely,
"C++ requires that every object has a unique definition. That rule would be broken if C++ allowed in-class definition of entities that needed to be stored in memory as objects."

Note that only static const integers can be treated as compile time constants. The compiler knows that the integer value will not change anytime and hence it can apply its own magic and apply optimizations, the compiler simply inlines such class members i.e, they are not stored in memory anymore, As the need of being stored in memory is removed, it gives such variables the exception to rule mentioned by Bjarne.

It is noteworthy to note here that even if static const integral values can have In-Class Initialization, taking address of such variables is not allowed. One can take the address of a static member if (and only if) it has an out-of-class definition.This further validates the reasoning above.

enums are allowed this because values of an enumerated type can be used where ints are expected.see citation above


How does this change in C++11?

C++11 relaxes the restriction to certain extent.

C++11 9.4.2 Static data members
§3

If a static data member is of const literal type, its declaration in the class definition can specify a brace-or-equal-initializer in which every initializer-clause that is an assignment-expression is a constant expression. A static data member of literal type can be declared in the class definition with the constexpr specifier; if so, its declaration shall specify a brace-or-equal-initializer in which every initializer-clause that is an assignment-expression is a constant expression. [ Note: In both these cases, the member may appear in constant expressions. —end note ] The member shall still be defined in a namespace scope if it is used in the program and the namespace scope definition shall not contain an initializer.

Also, C++11 will allow(§12.6.2.8) a non-static data member to be initialized where it is declared(in its class). This will mean much easy user semantics.

Note that these features have not yet been implemented in latest gcc 4.7, So you might still get compilation errors.

How can I get a specific parameter from location.search?

The easiest way is to have

if (document.location.search.indexOf('yourtext=') >= 0) {
    // your code
} else {
    // what happens?
}

indexOf()

The indexOf(text) function returns

  • A WHOLE NUMBER BELOW 0 when the text passed in the function is not in whatever variable or string you are looking for - in this case document.location.search.
  • A WHOLE NUMBER EQUAL TO 0 OR HIGHER when the text passed in the function is in whatever variable or string you are looking for - in this case document.location.search.

I hope this was useful, @gumbo

Angular-Material DateTime Picker Component?

Angular Material 10 now includes a new date range picker.

To use the new date range picker, you can use the mat-date-range-input and mat-date-range-picker components.

Example

HTML

<mat-form-field>
  <mat-label>Enter a date range</mat-label>
  <mat-date-range-input [rangePicker]="picker">
    <input matStartDate matInput placeholder="Start date">
    <input matEndDate matInput placeholder="End date">
  </mat-date-range-input>
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-date-range-picker #picker></mat-date-range-picker>
</mat-form-field>

You can read and learn more about this in their official documentation.

Unfortunately, they still haven't build a timepicker on this release.

How to display table data more clearly in oracle sqlplus

In case you have a dump made with sqlplus and the output is garbled as someone did not set those 3 values before, there's a way out.

Just a couple hours ago DB admin send me that ugly looking output of query executed in sqlplus (I dunno, maybe he hates me...). I had to find a way out: this is an awk script to parse that output to make it at least more readable. It's far not perfect, but I did not have enough time to polish it properly. Anyway, it does the job quite well.

awk ' function isDashed(ln){return ln ~ /^---+/};function addLn(){ln2=ln1; ln1=ln0;ln0=$0};function isLoaded(){return l==1||ln2!=""}; function printHeader(){hdr=hnames"\n"hdash;if(hdr!=lastHeader){lastHeader=hdr;print hdr};hnames="";hdash=""};function isHeaderFirstLn(){return isDashed(ln0) && !isDashed(ln1) && !isDashed(ln2) }; function isDataFirstLn(){return isDashed(ln2)&&!isDashed(ln1)&&!isDashed(ln0)}                         BEGIN{_d=1;h=1;hnames="";hdash="";val="";ln2="";ln1="";ln0="";fheadln=""}                                 { addLn();  if(!isLoaded()){next}; l=1;             if(h==1){if(!isDataFirstLn()){if(_d==0){hnames=hnames" "ln1;_d=1;}else{hdash=hdash" "ln1;_d=0}}else{_d=0;h=0;val=ln1;printHeader()}}else{if(!isHeaderFirstLn()){val=val" "ln1}else{print val;val="";_d=1;h=1;hnames=ln1}}   }END{if(val!="")print val}'

In case anyone else would like to try improve this script, below are the variables: hnames -- column names in the header, hdash - dashed below the header, h -- whether I'm currently parsing header (then ==1), val -- the data, _d - - to swap between hnames and hdash, ln0 - last line read, ln1 - line read previously (it's the one i'm actually working with), ln2 - line read before ln1

Happy parsing!

Oh, almost forgot... I use this to prettify sqlplus output myself:

[oracle@ora ~]$ cat prettify_sql 
set lines 256
set trimout on
set tab off
set pagesize 100
set colsep " | "

colsep is optional, but it makes output look like sqlite which is easier to parse using scripts.

EDIT: A little preview of parsed and non-parsed output

A little preview of parsed and non-parsed output

How to get absolute path to file in /resources folder of your project

The proper way that actually works:

URL resource = YourClass.class.getResource("abc");
Paths.get(resource.toURI()).toFile();

It doesn't matter now where the file in the classpath physically is, it will be found as long as the resource is actually a file and not a JAR entry.

(The seemingly obvious new File(resource.getPath()) doesn't work for all paths! The path is still URL-encoded!)

How to convert a number to string and vice versa in C++

How to convert a number to a string in C++03

  1. Do not use the itoa or itof functions because they are non-standard and therefore not portable.
  2. Use string streams

     #include <sstream>  //include this to use string streams
     #include <string> 
    
    int main()
    {    
        int number = 1234;
    
        std::ostringstream ostr; //output string stream
        ostr << number; //use the string stream just like cout,
        //except the stream prints not to stdout but to a string.
    
        std::string theNumberString = ostr.str(); //the str() function of the stream 
        //returns the string.
    
        //now  theNumberString is "1234"  
    }
    

    Note that you can use string streams also to convert floating-point numbers to string, and also to format the string as you wish, just like with cout

    std::ostringstream ostr;
    float f = 1.2;
    int i = 3;
    ostr << f << " + " i << " = " << f + i;   
    std::string s = ostr.str();
    //now s is "1.2 + 3 = 4.2" 
    

    You can use stream manipulators, such as std::endl, std::hex and functions std::setw(), std::setprecision() etc. with string streams in exactly the same manner as with cout

    Do not confuse std::ostringstream with std::ostrstream. The latter is deprecated

  3. Use boost lexical cast. If you are not familiar with boost, it is a good idea to start with a small library like this lexical_cast. To download and install boost and its documentation go here. Although boost isn't in C++ standard many libraries of boost get standardized eventually and boost is widely considered of the best C++ libraries.

    Lexical cast uses streams underneath, so basically this option is the same as the previous one, just less verbose.

    #include <boost/lexical_cast.hpp>
    #include <string>
    
    int main()
    {
       float f = 1.2;
       int i = 42;
       std::string sf = boost::lexical_cast<std::string>(f); //sf is "1.2"
       std::string si = boost::lexical_cast<std::string>(i); //sf is "42"
    }
    

How to convert a string to a number in C++03

  1. The most lightweight option, inherited from C, is the functions atoi (for integers (alphabetical to integer)) and atof (for floating-point values (alphabetical to float)). These functions take a C-style string as an argument (const char *) and therefore their usage may be considered a not exactly good C++ practice. cplusplus.com has easy-to-understand documentation on both atoi and atof including how they behave in case of bad input. However the link contains an error in that according to the standard if the input number is too large to fit in the target type, the behavior is undefined.

    #include <cstdlib> //the standard C library header
    #include <string>
    int main()
    {
        std::string si = "12";
        std::string sf = "1.2";
        int i = atoi(si.c_str()); //the c_str() function "converts" 
        double f = atof(sf.c_str()); //std::string to const char*
    }
    
  2. Use string streams (this time input string stream, istringstream). Again, istringstream is used just like cin. Again, do not confuse istringstream with istrstream. The latter is deprecated.

    #include <sstream>
    #include <string>
    int main()
    {
       std::string inputString = "1234 12.3 44";
       std::istringstream istr(inputString);
       int i1, i2;
       float f;
       istr >> i1 >> f >> i2;
       //i1 is 1234, f is 12.3, i2 is 44  
    }
    
  3. Use boost lexical cast.

    #include <boost/lexical_cast.hpp>
    #include <string>
    
    int main()
    {
       std::string sf = "42.2"; 
       std::string si = "42";
       float f = boost::lexical_cast<float>(sf); //f is 42.2
       int i = boost::lexical_cast<int>(si);  //i is 42
    }       
    

    In case of a bad input, lexical_cast throws an exception of type boost::bad_lexical_cast

How to open a workbook specifying its path

Workbooks.open("E:\sarath\PTMetrics\20131004\D8 L538-L550 16MY\D8 L538-L550_16MY_Powertrain Metrics_20131002.xlsm")

Or, in a more structured way...

Sub openwb()
    Dim sPath As String, sFile As String
    Dim wb As Workbook

    sPath = "E:\sarath\PTMetrics\20131004\D8 L538-L550 16MY\"
    sFile = sPath & "D8 L538-L550_16MY_Powertrain Metrics_20131002.xlsm"

    Set wb = Workbooks.Open(sFile)
End Sub

PHP PDO: charset, set names?

Prior to PHP 5.3.6, the charset option was ignored. If you're running an older version of PHP, you must do it like this:

<?php

    $dbh = new PDO("mysql:$connstr",  $user, $password);

    $dbh -> exec("set names utf8");

?>

How to set recurring schedule for xlsm file using Windows Task Scheduler

Code below copied from -> Here

First off, you must save your work book as a macro enabled work book. So it would need to be xlsm not an xlsx. Otherwise, excel will disable the macro's due to not being macro enabled.

Set your vbscript (C:\excel\tester.vbs). The example sub "test()" must be located in your modules on the excel document.

dim eApp
set eApp = GetObject("C:\excel\tester.xlsm")
eApp.Application.Run "tester.xlsm!test"
set eApp = nothing

Then set your Schedule, give it a name, and a username/password for offline access.

Then you have to set your actions and triggers.

Set your schedule(trigger)

Set your trigger

Action, set your vbscript to open with Cscript.exe so that it will be executed in the background and not get hung up by any error handling that vbcript has enabled.

Action Properties

How to input a regex in string.replace?

This tested snippet should do it:

import re
line = re.sub(r"</?\[\d+>", "", line)

Edit: Here's a commented version explaining how it works:

line = re.sub(r"""
  (?x) # Use free-spacing mode.
  <    # Match a literal '<'
  /?   # Optionally match a '/'
  \[   # Match a literal '['
  \d+  # Match one or more digits
  >    # Match a literal '>'
  """, "", line)

Regexes are fun! But I would strongly recommend spending an hour or two studying the basics. For starters, you need to learn which characters are special: "metacharacters" which need to be escaped (i.e. with a backslash placed in front - and the rules are different inside and outside character classes.) There is an excellent online tutorial at: www.regular-expressions.info. The time you spend there will pay for itself many times over. Happy regexing!

Handler "ExtensionlessUrlHandler-Integrated-4.0" has a bad module "ManagedPipelineHandler" in its module list

Make sure that you have set your application-site version from v2.0 to v4.0 in IIS Manager:

Application Pools > Your Application > Advanced Settings > .NET Framework Version

After that, install your ASP.NET.

For 32-Bit OS (Windows):

C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe -i

For 64-Bit OS (Windows):

C:\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -i

Restart your application-site in IIS Manager and enjoy.

Is there an XSLT name-of element?

<xsl:value-of select="name(.)" /> : <xsl:value-of select="."/>

Jquery UI datepicker. Disable array of Dates

For DD-MM-YY use this code:

var array = ["03-03-2017', '03-10-2017', '03-25-2017"]

$('#datepicker').datepicker({
    beforeShowDay: function(date){
    var string = jQuery.datepicker.formatDate('dd-mm-yy', date);
    return [ array.indexOf(string) == -1 ]
    }
});

function highlightDays(date) {
    for (var i = 0; i < dates.length; i++) {
    if (new Date(dates[i]).toString() == date.toString()) {
        return [true, 'highlight'];
    }
}
return [true, ''];
}

How to hide underbar in EditText

If you want this to affect all instances of EditText and any class that inherits from it, then you should set in your theme the value for the attribute, editTextBackground.

  <item name="android:editTextBackground">@drawable/bg_no_underline</item>

An example of the drawable I use is:

<inset xmlns:android="http://schemas.android.com/apk/res/android"
     android:insetLeft="@dimen/abc_edit_text_inset_horizontal_material"
     android:insetRight="@dimen/abc_edit_text_inset_horizontal_material"
     android:insetTop="@dimen/abc_edit_text_inset_top_material"
     android:insetBottom="@dimen/abc_edit_text_inset_bottom_material">
    <selector>
      <item android:drawable="@android:color/transparent"/>
    </selector>
</inset>

This is slightly modified version of what the default material design implementation is.

When applied it will make all your EditText remove the underline throughout the app, and you don't have to apply the style to each and every one manually.

Is it possible in Java to access private fields via reflection

Yes, it absolutely is - assuming you've got the appropriate security permissions. Use Field.setAccessible(true) first if you're accessing it from a different class.

import java.lang.reflect.*;

class Other
{
    private String str;
    public void setStr(String value)
    {
        str = value;
    }
}

class Test
{
    public static void main(String[] args)
        // Just for the ease of a throwaway test. Don't
        // do this normally!
        throws Exception
    {
        Other t = new Other();
        t.setStr("hi");
        Field field = Other.class.getDeclaredField("str");
        field.setAccessible(true);
        Object value = field.get(t);
        System.out.println(value);
    }
}

And no, you shouldn't normally do this... it's subverting the intentions of the original author of the class. For example, there may well be validation applied in any situation where the field can normally be set, or other fields may be changed at the same time. You're effectively violating the intended level of encapsulation.

How to add new column to an dataframe (to the front not end)?

df <- data.frame(b = c(1, 1, 1), c = c(2, 2, 2), d = c(3, 3, 3))
df
##   b c d
## 1 1 2 3
## 2 1 2 3
## 3 1 2 3

df <- data.frame(a = c(0, 0, 0), df)
df
##   a b c d
## 1 0 1 2 3
## 2 0 1 2 3
## 3 0 1 2 3

How to store date/time and timestamps in UTC time zone with JPA and Hibernate

With Spring Boot JPA, use the below code in your application.properties file and obviously you can modify timezone to your choice

spring.jpa.properties.hibernate.jdbc.time_zone = UTC

Then in your Entity class file,

@Column
private LocalDateTime created;

How can I rename a project folder from within Visual Studio?

Similar issues arise when a new project has to be created, and you want a different project folder name than the project name.

When you create a new project, it gets stored at

./path/to/pro/ject/YourProject/YourProject.**proj

Let's assume you wanted to have it directly in the ject folder:

./path/to/pro/ject/YourProject.**proj

My workaround to accomplish this is to create the project with the last part of the path as its name, so that it doesn't create an additional directory:

./path/to/pro/ject/ject.**proj

When you now rename the project from within Visual Studio, you achieve the goal without having to leave Visual Studio:

./path/to/pro/ject/YourProject.**proj

The downside of this approach is that you have to adjust the default namespace and the name of the Output binary as well, and that you have to update namespaces in all files that are included within the project template.

Execute a command in command prompt using excel VBA

The S parameter does not do anything on its own.

/S      Modifies the treatment of string after /C or /K (see below) 
/C      Carries out the command specified by string and then terminates  
/K      Carries out the command specified by string but remains  

Try something like this instead

Call Shell("cmd.exe /S /K" & "perl a.pl c:\temp", vbNormalFocus)

You may not even need to add "cmd.exe" to this command unless you want a command window to open up when this is run. Shell should execute the command on its own.

Shell("perl a.pl c:\temp")



-Edit-
To wait for the command to finish you will have to do something like @Nate Hekman shows in his answer here

Dim wsh As Object
Set wsh = VBA.CreateObject("WScript.Shell")
Dim waitOnReturn As Boolean: waitOnReturn = True
Dim windowStyle As Integer: windowStyle = 1

wsh.Run "cmd.exe /S /C perl a.pl c:\temp", windowStyle, waitOnReturn

Set the layout weight of a TextView programmatically

TextView txtview = new TextView(v.getContext());
LayoutParams params = new LinearLayout.LayoutParams(0, LayoutParams.WRAP_CONTENT, 1f);
txtview.setLayoutParams(params);

1f is denotes as weight=1; you can give 2f or 3f, views will move accoding to the space

Why is the time complexity of both DFS and BFS O( V + E )

Your sum

v1 + (incident edges) + v2 + (incident edges) + .... + vn + (incident edges)

can be rewritten as

(v1 + v2 + ... + vn) + [(incident_edges v1) + (incident_edges v2) + ... + (incident_edges vn)]

and the first group is O(N) while the other is O(E).

How do I copy a hash in Ruby?

I am also a newbie to Ruby and I faced similar issues in duplicating a hash. Use the following. I've got no idea about the speed of this method.

copy_of_original_hash = Hash.new.merge(original_hash)

CORS error :Request header field Authorization is not allowed by Access-Control-Allow-Headers in preflight response

First you need to install cors by using below command :

npm install cors --save

Now add the following code to your app starting file like ( app.js or server.js)

var express = require('express');
var app = express();

var cors = require('cors');
var bodyParser = require('body-parser');

//enables cors
app.use(cors({
  'allowedHeaders': ['sessionId', 'Content-Type'],
  'exposedHeaders': ['sessionId'],
  'origin': '*',
  'methods': 'GET,HEAD,PUT,PATCH,POST,DELETE',
  'preflightContinue': false
}));

require('./router/index')(app);

Creating a LinkedList class from scratch

How about a fully functional implementation of a non-recursive Linked List?

I created this for my Algorithms I class as a stepping stone to gain a better understanding before moving onto writing a doubly-linked queue class for an assignment.

Here's the code:

import java.util.Iterator;
import java.util.NoSuchElementException;

public class LinkedList<T> implements Iterable<T> {
    private Node first;
    private Node last;
    private int N;

    public LinkedList() {
        first = null;
        last = null;
        N = 0;
    }

    public void add(T item) {
        if (item == null) { throw new NullPointerException("The first argument for addLast() is null."); }
        if (!isEmpty()) {
            Node prev = last;
            last = new Node(item, null);
            prev.next = last;
        }
        else {
            last = new Node(item, null);
            first = last;
        }
        N++;
    }

    public boolean remove(T item) {
        if (isEmpty()) { throw new IllegalStateException("Cannot remove() from and empty list."); }
        boolean result = false;
        Node prev = first;
        Node curr = first;
        while (curr.next != null || curr == last) {
            if (curr.data.equals(item)) {
                // remove the last remaining element
                if (N == 1) { first = null; last = null; }
                // remove first element
                else if (curr.equals(first)) { first = first.next; }
                // remove last element
                else if (curr.equals(last)) { last = prev; last.next = null; }
                // remove element
                else { prev.next = curr.next; }
                N--;
                result = true;
                break;
            }
            prev = curr;
            curr = prev.next;
        }
        return result;
    }

    public int size() {
        return N;
    }

    public boolean isEmpty() {
        return N == 0;
    }

    private class Node {
        private T data;
        private Node next;

        public Node(T data, Node next) {
            this.data = data;
            this.next = next;
        }
    }

    public Iterator<T> iterator() { return new LinkedListIterator(); }

    private class LinkedListIterator implements Iterator<T> {
        private Node current = first;

        public T next() {
            if (!hasNext()) { throw new NoSuchElementException(); }
            T item = current.data;
            current = current.next;
            return item;
        }

        public boolean hasNext() { return current != null; }

        public void remove() { throw new UnsupportedOperationException(); }
    }

    @Override public String toString() {
        StringBuilder s = new StringBuilder();
        for (T item : this)
            s.append(item + " ");
        return s.toString();
    }

    public static void main(String[] args) {
        LinkedList<String> list = new LinkedList<>();
        while(!StdIn.isEmpty()) {
            String input = StdIn.readString();
            if (input.equals("print")) { StdOut.println(list.toString()); continue; }
            if (input.charAt(0) == ('+')) { list.add(input.substring(1)); continue; }
            if (input.charAt(0) == ('-')) { list.remove(input.substring(1)); continue; }
            break;
        }
    }
}

Note: It's a pretty basic implementation of a singly-linked-list. The 'T' type is a generic type placeholder. Basically, this linked list should work with any type that inherits from Object. If you use it for primitive types be sure to use the nullable class equivalents (ex 'Integer' for the 'int' type). The 'last' variable isn't really necessary except that it shortens insertions to O(1) time. Removals are slow since they run in O(N) time but it allows you to remove the first occurrence of a value in the list.

If you want you could also look into implementing:

  • addFirst() - add a new item to the beginning of the LinkedList
  • removeFirst() - remove the first item from the LinkedList
  • removeLast() - remove the last item from the LinkedList
  • addAll() - add a list/array of items to the LinkedList
  • removeAll() - remove a list/array of items from the LinkedList
  • contains() - check to see if the LinkedList contains an item
  • contains() - clear all items in the LinkedList

Honestly, it only takes a few lines of code to make this a doubly-linked list. The main difference between this and a doubly-linked-list is that the Node instances of a doubly-linked list require an additional reference that points to the previous element in the list.

The benefit of this over a recursive implementation is that it's faster and you don't have to worry about flooding the stack when you traverse large lists.

There are 3 commands to test this in the debugger/console:

  • Prefixing a value by a '+' will add it to the list.
  • Prefixing with a '-' will remove the first occurrence from the list.
  • Typing 'print' will print out the list with the values separated by spaces.

If you have never seen the internals of how one of these works I suggest you step through the following in the debugger:

  • add() - tacks a new node onto the end or initializes the first/last values if the list is empty
  • remove() - walks the list from the start-to-end. If it finds a match it removes that item and connects the broken links between the previous and next links in the chain. Special exceptions are added when there is no previous or next link.
  • toString() - uses the foreach iterator to simply walk the list chain from beginning-to-end.

While there are better and more efficient approaches for lists like array-lists, understanding how the application traverses via references/pointers is integral to understanding how many higher-level data structures work.

What and where are the stack and heap?

The stack is the memory set aside as scratch space for a thread of execution. When a function is called, a block is reserved on the top of the stack for local variables and some bookkeeping data. When that function returns, the block becomes unused and can be used the next time a function is called. The stack is always reserved in a LIFO (last in first out) order; the most recently reserved block is always the next block to be freed. This makes it really simple to keep track of the stack; freeing a block from the stack is nothing more than adjusting one pointer.

The heap is memory set aside for dynamic allocation. Unlike the stack, there's no enforced pattern to the allocation and deallocation of blocks from the heap; you can allocate a block at any time and free it at any time. This makes it much more complex to keep track of which parts of the heap are allocated or free at any given time; there are many custom heap allocators available to tune heap performance for different usage patterns.

Each thread gets a stack, while there's typically only one heap for the application (although it isn't uncommon to have multiple heaps for different types of allocation).

To answer your questions directly:

To what extent are they controlled by the OS or language runtime?

The OS allocates the stack for each system-level thread when the thread is created. Typically the OS is called by the language runtime to allocate the heap for the application.

What is their scope?

The stack is attached to a thread, so when the thread exits the stack is reclaimed. The heap is typically allocated at application startup by the runtime, and is reclaimed when the application (technically process) exits.

What determines the size of each of them?

The size of the stack is set when a thread is created. The size of the heap is set on application startup, but can grow as space is needed (the allocator requests more memory from the operating system).

What makes one faster?

The stack is faster because the access pattern makes it trivial to allocate and deallocate memory from it (a pointer/integer is simply incremented or decremented), while the heap has much more complex bookkeeping involved in an allocation or deallocation. Also, each byte in the stack tends to be reused very frequently which means it tends to be mapped to the processor's cache, making it very fast. Another performance hit for the heap is that the heap, being mostly a global resource, typically has to be multi-threading safe, i.e. each allocation and deallocation needs to be - typically - synchronized with "all" other heap accesses in the program.

A clear demonstration:
Image source: vikashazrati.wordpress.com

sql try/catch rollback/commit - preventing erroneous commit after rollback

In your first example, you are correct. The batch will hit the commit transaction, regardless of whether the try block fires.

In your second example, I agree with other commenters. Using the success flag is unnecessary.

I consider the following approach to be, essentially, a light weight best practice approach.

If you want to see how it handles an exception, change the value on the second insert from 255 to 256.

CREATE TABLE #TEMP ( ID TINYINT NOT NULL );
INSERT  INTO #TEMP( ID ) VALUES  ( 1 )

BEGIN TRY
    BEGIN TRANSACTION

    INSERT  INTO #TEMP( ID ) VALUES  ( 2 )
    INSERT  INTO #TEMP( ID ) VALUES  ( 255 )

    COMMIT TRANSACTION
END TRY
BEGIN CATCH
    DECLARE 
        @ErrorMessage NVARCHAR(4000),
        @ErrorSeverity INT,
        @ErrorState INT;
    SELECT 
        @ErrorMessage = ERROR_MESSAGE(),
        @ErrorSeverity = ERROR_SEVERITY(),
        @ErrorState = ERROR_STATE();
    RAISERROR (
        @ErrorMessage,
        @ErrorSeverity,
        @ErrorState    
        );
    ROLLBACK TRANSACTION
END CATCH

SET NOCOUNT ON

SELECT ID
FROM #TEMP

DROP TABLE #TEMP

How to set environment variables in PyCharm?

I was able to figure out this using a PyCharm plugin called EnvFile. This plugin, basically allows setting environment variables to run configurations from one or multiple files.

The installation is pretty simple:

Preferences > Plugins > Browse repositories... > Search for "Env File" > Install Plugin.

Then, I created a file, in my project root, called environment.env which contains:

DATABASE_URL=postgres://127.0.0.1:5432/my_db_name
DEBUG=1

Then I went to Run->Edit Configurations, and I followed the steps in the next image:

Set Environment Variables

In 3, I chose the file environment.env, and then I could just click the play button in PyCharm, and everything worked like a charm.

How to show PIL Image in ipython notebook

I suggest following installation by no image show img.show() (from PIL import Image)

$ sudo apt-get install imagemagick

How to transfer data from JSP to servlet when submitting HTML form

first up on create your jsp file : and write the text field which you want
for ex:

after that create your servlet class:

public class test{

protected void doGet(paramter , paramter){

String name  = request.getparameter("name");
 }

}

Iterate through a HashMap

Extracted from the reference How to Iterate Over a Map in Java:

There are several ways of iterating over a Map in Java. Let's go over the most common methods and review their advantages and disadvantages. Since all maps in Java implement the Map interface, the following techniques will work for any map implementation (HashMap, TreeMap, LinkedHashMap, Hashtable, etc.)

Method #1: Iterating over entries using a For-Each loop.

This is the most common method and is preferable in most cases. It should be used if you need both map keys and values in the loop.

Map<Integer, Integer> map = new HashMap<Integer, Integer>();
for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
    System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}

Note that the For-Each loop was introduced in Java 5, so this method is working only in newer versions of the language. Also a For-Each loop will throw NullPointerException if you try to iterate over a map that is null, so before iterating you should always check for null references.

Method #2: Iterating over keys or values using a For-Each loop.

If you need only keys or values from the map, you can iterate over keySet or values instead of entrySet.

Map<Integer, Integer> map = new HashMap<Integer, Integer>();

// Iterating over keys only
for (Integer key : map.keySet()) {
    System.out.println("Key = " + key);
}

// Iterating over values only
for (Integer value : map.values()) {
    System.out.println("Value = " + value);
}

This method gives a slight performance advantage over entrySet iteration (about 10% faster) and is more clean.

Method #3: Iterating using Iterator.

Using Generics:

Map<Integer, Integer> map = new HashMap<Integer, Integer>();
Iterator<Map.Entry<Integer, Integer>> entries = map.entrySet().iterator();
while (entries.hasNext()) {
    Map.Entry<Integer, Integer> entry = entries.next();
    System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}

Without Generics:

Map map = new HashMap();
Iterator entries = map.entrySet().iterator();
while (entries.hasNext()) {
    Map.Entry entry = (Map.Entry) entries.next();
    Integer key = (Integer)entry.getKey();
    Integer value = (Integer)entry.getValue();
    System.out.println("Key = " + key + ", Value = " + value);
}

You can also use same technique to iterate over keySet or values.

This method might look redundant, but it has its own advantages. First of all, it is the only way to iterate over a map in older versions of Java. The other important feature is that it is the only method that allows you to remove entries from the map during iteration by calling iterator.remove(). If you try to do this during For-Each iteration you will get "unpredictable results" according to Javadoc.

From a performance point of view this method is equal to a For-Each iteration.

Method #4: Iterating over keys and searching for values (inefficient).

Map<Integer, Integer> map = new HashMap<Integer, Integer>();
for (Integer key : map.keySet()) {
    Integer value = map.get(key);
    System.out.println("Key = " + key + ", Value = " + value);
}

This might look like a cleaner alternative for method #1, but in practice it is pretty slow and inefficient as getting values by a key might be time-consuming (this method in different Map implementations is 20%-200% slower than method #1). If you have FindBugs installed, it will detect this and warn you about inefficient iteration. This method should be avoided.

Conclusion:

If you need only keys or values from the map, use method #2. If you are stuck with older version of Java (less than 5) or planning to remove entries during iteration, you have to use method #3. Otherwise use method #1.

How to get box-shadow on left & right sides only

Another idea could be creating a dark blurred pseudo element eventually with transparency to imitate shadow. Make it with slightly less height and more width i.g.

Refresh Page and Keep Scroll Position

UPDATE

You can use document.location.reload(true) as mentioned below instead of the forced trick below.

Replace your HTML with this:

<!DOCTYPE html>
<html>
    <head>
        <style type="text/css">
            body { 
                background-image: url('../Images/Black-BackGround.gif');
                background-repeat: repeat;
            }
            body td {
               font-Family: Arial; 
               font-size: 12px; 
            }
            #Nav a { 
                position:relative; 
                display:block; 
                text-decoration: none; 
                color:black; 
            }
        </style>
        <script type="text/javascript">
            function refreshPage () {
                var page_y = document.getElementsByTagName("body")[0].scrollTop;
                window.location.href = window.location.href.split('?')[0] + '?page_y=' + page_y;
            }
            window.onload = function () {
                setTimeout(refreshPage, 35000);
                if ( window.location.href.indexOf('page_y') != -1 ) {
                    var match = window.location.href.split('?')[1].split("&")[0].split("=");
                    document.getElementsByTagName("body")[0].scrollTop = match[1];
                }
            }
        </script>
    </head>
    <body><!-- BODY CONTENT HERE --></body>
</html>

Read input from console in Ruby?

There are many ways to take input from the users. I personally like using the method gets. When you use gets, it gets the string that you typed, and that includes the ENTER key that you pressed to end your input.

name = gets
"mukesh\n"

You can see this in irb; type this and you will see the \n, which is the “newline” character that the ENTER key produces: Type name = gets you will see somethings like "mukesh\n" You can get rid of pesky newline character using chomp method.

The chomp method gives you back the string, but without the terminating newline. Beautiful chomp method life saviour.

name = gets.chomp
"mukesh"

You can also use terminal to read the input. ARGV is a constant defined in the Object class. It is an instance of the Array class and has access to all the array methods. Since it’s an array, even though it’s a constant, its elements can be modified and cleared with no trouble. By default, Ruby captures all the command line arguments passed to a Ruby program (split by spaces) when the command-line binary is invoked and stores them as strings in the ARGV array.

When written inside your Ruby program, ARGV will take take a command line command that looks like this:

test.rb hi my name is mukesh

and create an array that looks like this:

["hi", "my", "name", "is", "mukesh"]

But, if I want to passed limited input then we can use something like this.

test.rb 12 23

and use those input like this in your program:

a = ARGV[0]
b = ARGV[1]

How to export/import PuTTy sessions list?

When I tried the other solutions I got this error:

Registry editing has been disabled by your administrator.

Phooey to that, I say!

I put together the below powershell scripts for exporting and importing PuTTY settings. The exported file is a windows .reg file and will import cleanly if you have permission, otherwise use import.ps1 to load it.

Warning: messing with the registry like this is a Bad Idea™, and I don't really know what I'm doing. Use the below scripts at your own risk, and be prepared to have your IT department re-image your machine and ask you uncomfortable questions about what you were doing.

On the source machine:

.\export.ps1

On the target machine:

.\import.ps1 > cmd.ps1
# Examine cmd.ps1 to ensure it doesn't do anything nasty
.\cmd.ps1

export.ps1

# All settings
$registry_path = "HKCU:\Software\SimonTatham"
# Only sessions
#$registry_path = "HKCU:\Software\SimonTatham\PuTTY\Sessions"
$output_file = "putty.reg"

$registry = ls "$registry_path" -Recurse

"Windows Registry Editor Version 5.00" | Out-File putty.reg
"" | Out-File putty.reg -Append

foreach ($reg in $registry) {
  "[$reg]" | Out-File putty.reg -Append
  foreach ($prop in $reg.property) {
    $propval = $reg.GetValue($prop)
    if ("".GetType().Equals($propval.GetType())) {
      '"' + "$prop" + '"' + "=" + '"' + "$propval" + '"' | Out-File putty.reg -Append
    } elseif ($propval -is [int]) {
      $hex = "{0:x8}" -f $propval
      '"' + "$prop" + '"' + "=dword:" + $hex | Out-File putty.reg -Append
    }
  }
  "" | Out-File putty.reg -Append
}

import.ps1

$input_file = "putty.reg"

$content = Get-Content "$input_file"

"Push-Location"
"cd HKCU:\"

foreach ($line in $content) { 
  If ($line.StartsWith("Windows Registry Editor")) {
    # Ignore the header
  } ElseIf ($line.startswith("[")) {
    $section = $line.Trim().Trim('[', ']')
    'New-Item -Path "' + $section + '" -Force' | %{ $_ -replace 'HKEY_CURRENT_USER\\', '' }
  } ElseIf ($line.startswith('"')) {
    $linesplit = $line.split('=', 2)
    $key = $linesplit[0].Trim('"')
    if ($linesplit[1].StartsWith('"')) {
      $value = $linesplit[1].Trim().Trim('"')
    } ElseIf ($linesplit[1].StartsWith('dword:')) {
      $value = [Int32]('0x' + $linesplit[1].Trim().Split(':', 2)[1])
      'New-ItemProperty "' + $section + '" "' + $key + '" -PropertyType dword -Force' | %{ $_ -replace 'HKEY_CURRENT_USER\\', '' }
    } Else {
      Write-Host "Error: unknown property type: $linesplit[1]"
      exit
    }
    'Set-ItemProperty -Path "' + $section + '" -Name "' + $key + '" -Value "' + $value + '"' | %{ $_ -replace 'HKEY_CURRENT_USER\\', '' }
  }
}

"Pop-Location"

Apologies for the non-idiomatic code, I'm not very familiar with Powershell. Improvements are welcome!

SQL Server using wildcard within IN

The IN operator is nothing but a fancy OR of '=' comparisons. In fact it is so 'nothing but' that in SQL 2000 there was a stack overflow bug due to expansion of the IN into ORs when the list contained about 10k entries (yes, there are people writing 10k IN entries...). So you can't use any wildcard matching in it.

how to increase sqlplus column output length?

What I use:

set long 50000
set linesize 130

col x format a80 word_wrapped;
select dbms_metadata.get_ddl('TABLESPACE','LM_THIN_DATA') x from dual;

Or am I missing something?

/etc/apt/sources.list" E212: Can't open file for writing

For me there was was quite a simple solution. I was trying to edit/create a file in a folder that didn't exist. As I was already in the folder I was trying to edit/create a file in.

i.e. pwd folder/file

and was typing

sudo vim folder/file

and rather obviously it was looking for the folder in the folder and failing to save.

adding a datatable in a dataset

I assume that you haven't set the TableName property of the DataTable, for example via constructor:

var tbl = new DataTable("dtImage");

If you don't provide a name, it will be automatically created with "Table1", the next table will get "Table2" and so on.

Then the solution would be to provide the TableName and then check with Contains(nameOfTable).

To clarify it: You'll get an ArgumentException if that DataTable already belongs to the DataSet (the same reference). You'll get a DuplicateNameException if there's already a DataTable in the DataSet with the same name(not case-sensitive).

http://msdn.microsoft.com/en-us/library/as4zy2kc.aspx

Inversion of Control vs Dependency Injection

IOC (Inversion Of Control): Giving control to the container to get an instance of the object is called Inversion of Control, means instead of you are creating an object using the new operator, let the container do that for you.

DI (Dependency Injection): Way of injecting properties to an object is called Dependency Injection.

We have three types of Dependency Injection:

  1. Constructor Injection
  2. Setter/Getter Injection
  3. Interface Injection

Spring supports only Constructor Injection and Setter/Getter Injection.

Set Focus After Last Character in Text Box

var val =$("#inputname").val();
$("#inputname").removeAttr('value').attr('value', val).focus();
// I think this is beter for all browsers...

Sending JWT token in the headers with Postman

Here is an image if it helps :)

Postman

Update:

The postman team added "Bearer token" to the "authorization tab": Updated postman

Detect viewport orientation, if orientation is Portrait display alert message advising user of instructions

This is what I use.

function getOrientation() {

    // if window.orientation is available...
    if( window.orientation && typeof window.orientation === 'number' ) {

        // ... and if the absolute value of orientation is 90...
        if( Math.abs( window.orientation ) == 90 ) {

              // ... then it's landscape
              return 'landscape';

        } else {

              // ... otherwise it's portrait
              return 'portrait';

        }

    } else {

        return false; // window.orientation not available

    }

}

Implementation

window.addEventListener("orientationchange", function() {

     // if orientation is landscape...
     if( getOrientation() === 'landscape' ) {

         // ...do your thing

    }

}, false);

Convert string into integer in bash script - "Leading Zero" number error

You could also use bc

hour=8
result=$(echo "$hour + 1" | bc)
echo $result
9

Couldn't load memtrack module Logcat Error

This error, as you can read on the question linked in comments above, results to be:

"[...] a problem with loading {some} hardware module. This could be something to do with GPU support, sdcard handling, basically anything."

The step 1 below should resolve this problem. Also as I can see, you have some strange package names inside your manifest:

  • package="com.example.hive" in <manifest> tag,
  • android:name="com.sit.gems.app.GemsApplication" for <application>
  • and android:name="com.sit.gems.activity" in <activity>

As you know, these things do not prevent your app to be displayed. But I think:

the Couldn't load memtrack module error could occur because of emulators configurations problems and, because your project contains many organization problems, it might help to give a fresh redesign.

For better using and with few things, this can be resolved by following these tips:


1. Try an other emulator...

And even a real device! The memtrack module error seems related to your emulator. So change it into Run configuration, don't forget to change the API too.


2. OpenGL error logs

For OpenGl errors, as called unimplemented OpenGL ES API, it's not an error but a statement! You should enable it in your manifest (you can read this answer if you're using GLSurfaceView inside HomeActivity.java, it might help you):

<uses-feature android:glEsVersion="0x00020000"></uses-feature>  
// or
<uses-feature android:glEsVersion="0x00010001" android:required="true" />

3. Use the same package

Don't declare different package names to all the tags in Manifest. You should have the same for Manifest, Activities, etc. Something like this looks right:

<!-- set the general package -->
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.sit.gems.activity"
    android:versionCode="1"
    android:versionName="1.0" >

    <!-- don't set a package name in <application> -->
    <application ... >

        <!-- then, declare the activities -->
        <activity
            android:name="com.sit.gems.activity.SplashActivity" ... >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <!-- same package here -->
        <activity
            android:name="com.sit.gems.activity.HomeActivity" ... >
        </activity>
    </application>
</manifest>  

4. Don't get lost with layouts:

You should set another layout for SplashScreenActivity.java because you're not using the TabHost for the splash screen and this is not a safe resource way. Declare a specific layout with something different, like the app name and the logo:

// inside SplashScreen class
setContentView(R.layout.splash_screen);

// layout splash_screen.xml
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent" 
     android:gravity="center"
     android:text="@string/appname" />  

Avoid using a layout in activities which don't use it.


5. Splash Screen?

Finally, I don't understand clearly the purpose of your SplashScreenActivity. It sets a content view and directly finish. This is useless.

As its name is Splash Screen, I assume that you want to display a screen before launching your HomeActivity. Therefore, you should do this and don't use the TabHost layout ;):

// FragmentActivity is also useless here! You don't use a Fragment into it, so, use traditional Activity
public class SplashActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // set your splash_screen layout
        setContentView(R.layout.splash_screen);

        // create a new Thread
        new Thread(new Runnable() {
            public void run() {
                try {
                    // sleep during 800ms
                    Thread.sleep(800);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                // start HomeActivity
                startActivity(new Intent(SplashActivity.this, HomeActivity.class));
                SplashActivity.this.finish();
            }
        }).start();
    }
}  

I hope this kind of tips help you to achieve what you want.
If it's not the case, let me know how can I help you.

Java: Get last element after split

I guess you want to do this in i line. It is possible (a bit of juggling though =^)

new StringBuilder(new StringBuilder("Düsseldorf - Zentrum - Günnewig Uebachs").reverse().toString().split(" - ")[0]).reverse()

tadaa, one line -> the result you want (if you split on " - " (space minus space) instead of only "-" (minus) you will loose the annoying space before the partition too =^) so "Günnewig Uebachs" instead of " Günnewig Uebachs" (with a space as first character)

Nice extra -> no need for extra JAR files in the lib folder so you can keep your application light weight.

How do I check if an object's type is a particular subclass in C++?

In c# you can simply say:

if (myObj is Car) {

}

C++ How do I convert a std::chrono::time_point to long and back

std::chrono::time_point<std::chrono::system_clock> now = std::chrono::system_clock::now();

This is a great place for auto:

auto now = std::chrono::system_clock::now();

Since you want to traffic at millisecond precision, it would be good to go ahead and covert to it in the time_point:

auto now_ms = std::chrono::time_point_cast<std::chrono::milliseconds>(now);

now_ms is a time_point, based on system_clock, but with the precision of milliseconds instead of whatever precision your system_clock has.

auto epoch = now_ms.time_since_epoch();

epoch now has type std::chrono::milliseconds. And this next statement becomes essentially a no-op (simply makes a copy and does not make a conversion):

auto value = std::chrono::duration_cast<std::chrono::milliseconds>(epoch);

Here:

long duration = value.count();

In both your and my code, duration holds the number of milliseconds since the epoch of system_clock.

This:

std::chrono::duration<long> dur(duration);

Creates a duration represented with a long, and a precision of seconds. This effectively reinterpret_casts the milliseconds held in value to seconds. It is a logic error. The correct code would look like:

std::chrono::milliseconds dur(duration);

This line:

std::chrono::time_point<std::chrono::system_clock> dt(dur);

creates a time_point based on system_clock, with the capability of holding a precision to the system_clock's native precision (typically finer than milliseconds). However the run-time value will correctly reflect that an integral number of milliseconds are held (assuming my correction on the type of dur).

Even with the correction, this test will (nearly always) fail though:

if (dt != now)

Because dt holds an integral number of milliseconds, but now holds an integral number of ticks finer than a millisecond (e.g. microseconds or nanoseconds). Thus only on the rare chance that system_clock::now() returned an integral number of milliseconds would the test pass.

But you can instead:

if (dt != now_ms)

And you will now get your expected result reliably.

Putting it all together:

int main ()
{
    auto now = std::chrono::system_clock::now();
    auto now_ms = std::chrono::time_point_cast<std::chrono::milliseconds>(now);

    auto value = now_ms.time_since_epoch();
    long duration = value.count();

    std::chrono::milliseconds dur(duration);

    std::chrono::time_point<std::chrono::system_clock> dt(dur);

    if (dt != now_ms)
        std::cout << "Failure." << std::endl;
    else
        std::cout << "Success." << std::endl;
}

Personally I find all the std::chrono overly verbose and so I would code it as:

int main ()
{
    using namespace std::chrono;
    auto now = system_clock::now();
    auto now_ms = time_point_cast<milliseconds>(now);

    auto value = now_ms.time_since_epoch();
    long duration = value.count();

    milliseconds dur(duration);

    time_point<system_clock> dt(dur);

    if (dt != now_ms)
        std::cout << "Failure." << std::endl;
    else
        std::cout << "Success." << std::endl;
}

Which will reliably output:

Success.

Finally, I recommend eliminating temporaries to reduce the code converting between time_point and integral type to a minimum. These conversions are dangerous, and so the less code you write manipulating the bare integral type the better:

int main ()
{
    using namespace std::chrono;
    // Get current time with precision of milliseconds
    auto now = time_point_cast<milliseconds>(system_clock::now());
    // sys_milliseconds is type time_point<system_clock, milliseconds>
    using sys_milliseconds = decltype(now);
    // Convert time_point to signed integral type
    auto integral_duration = now.time_since_epoch().count();
    // Convert signed integral type to time_point
    sys_milliseconds dt{milliseconds{integral_duration}};
    // test
    if (dt != now)
        std::cout << "Failure." << std::endl;
    else
        std::cout << "Success." << std::endl;
}

The main danger above is not interpreting integral_duration as milliseconds on the way back to a time_point. One possible way to mitigate that risk is to write:

    sys_milliseconds dt{sys_milliseconds::duration{integral_duration}};

This reduces risk down to just making sure you use sys_milliseconds on the way out, and in the two places on the way back in.

And one more example: Let's say you want to convert to and from an integral which represents whatever duration system_clock supports (microseconds, 10th of microseconds or nanoseconds). Then you don't have to worry about specifying milliseconds as above. The code simplifies to:

int main ()
{
    using namespace std::chrono;
    // Get current time with native precision
    auto now = system_clock::now();
    // Convert time_point to signed integral type
    auto integral_duration = now.time_since_epoch().count();
    // Convert signed integral type to time_point
    system_clock::time_point dt{system_clock::duration{integral_duration}};
    // test
    if (dt != now)
        std::cout << "Failure." << std::endl;
    else
        std::cout << "Success." << std::endl;
}

This works, but if you run half the conversion (out to integral) on one platform and the other half (in from integral) on another platform, you run the risk that system_clock::duration will have different precisions for the two conversions.

Android: How to change the ActionBar "Home" Icon to be something other than the app icon?

In AndroidManifest.xml:

<application
    android:icon="@drawable/launcher"
    android:label="@string/app_name"
    android:name="com..."
    android:theme="@style/Theme">...</Application>

In styles.xml: (See android:icon)

<style name="Theme" parent="@android:style/Theme.Holo.Light">
    <item name="android:actionBarStyle">@style/ActionBar</item>
</style>
<style name="ActionBar" parent="@android:style/Widget.Holo.Light.ActionBar">
    <item name="android:icon">@drawable/icon</item>
</style>

HttpRequest maximum allowable size in tomcat?

The full answer

1. The default (fresh install of tomcat)

When you download tomcat from their official website (of today that's tomcat version 9.0.26), all the apps you installed to tomcat can handle HTTP requests of unlimited size, given that the apps themselves do not have any limits on request size.

However, when you try to upload an app in tomcat's manager app, that app has a default war file limit of 50MB. If you're trying to install Jenkins for example which is 77 MB as ot today, it will fail.

2. Configure tomcat's per port http request size limit

Tomcat itself has size limit for each port, and this is defined in conf\server.xml. This is controlled by maxPostSize attribute of each Connector(port). If this attribute does not exist, which it is by default, there is no limit on the request size.

To add a limit to a specific port, set a byte size for the attribute. For example, the below config for the default 8080 port limits request size to 200 MB. This means that all the apps installed under port 8080 now has the size limit of 200MB

<Connector port="8080" protocol="HTTP/1.1"
           connectionTimeout="20000"
           redirectPort="8443"
           maxPostSize="209715200" />

3. Configure app level size limit

After passing the port level size limit, you can still configure app level limit. This also means that app level limit should be less than port level limit. The limit can be done through annotation within each servlet, or in the web.xml file. Again, if this is not set at all, there is no limit on request size.

To set limit through java annotation

@WebServlet("/uploadFiles")
@MultipartConfig( fileSizeThreshold = 0, maxFileSize = 209715200, maxRequestSize = 209715200)
public class FileUploadServlet extends HttpServlet {

    public void doPost(HttpServletRequest request, HttpServletResponse response) {
        // ...
    }
}

To set limit through web.xml

<web-app>
  ...
  <servlet>
    ...
    <multipart-config>
      <file-size-threshold>0</file-size-threshold>
      <max-file-size>209715200</max-file-size>
      <max-request-size>209715200</max-request-size>
    </multipart-config>
    ...
  </servlet>
  ...
</web-app>

4. Appendix - If you see file upload size error when trying to install app through Tomcat's Manager app

Tomcat's Manager app (by default localhost:8080/manager) is nothing but a default web app. By default that app has a web.xml configuration of request limit of 50MB. To install (upload) app with size greater than 50MB through this manager app, you have to change the limit. Open the manager app's web.xml file from webapps\manager\WEB-INF\web.xml and follow the above guide to change the size limit and finally restart tomcat.

Jquery/Ajax Form Submission (enctype="multipart/form-data" ). Why does 'contentType:False' cause undefined index in PHP?

Please set your form action attribute as below it will solve your problem.

<form name="addProductForm" id="addProductForm" action="javascript:;" enctype="multipart/form-data" method="post" accept-charset="utf-8">

jQuery code:

$(document).ready(function () {
    $("#addProductForm").submit(function (event) {

        //disable the default form submission
        event.preventDefault();
        //grab all form data  
        var formData = $(this).serialize();

        $.ajax({
            url: 'addProduct.php',
            type: 'POST',
            data: formData,
            async: false,
            cache: false,
            contentType: false,
            processData: false,
            success: function () {
                alert('Form Submitted!');
            },
            error: function(){
                alert("error in ajax form submission");
            }
        });

        return false;
    });
});

Android SDK Manager Not Installing Components

In windows 8:

  • right click on windows button
  • List item
  • CDM as administrator
  • Press 'yes'
  • paste this $ C:\xxx\xxx\AppData\Local\Android\sdk\tools\android.bat

Loop through all elements in XML using NodeList

Here is another way to loop through XML elements using JDOM.

        List<Element> nodeNodes = inputNode.getChildren();
        if (nodeNodes != null) {
            for (Element nodeNode : nodeNodes) {
                List<Element> elements = nodeNode.getChildren(elementName);
                if (elements != null) {
                    elements.size();
                    nodeNodes.removeAll(elements);
                }
            }

Converting two lists into a matrix

Assuming lengths of portfolio and index are the same:

matrix = []
for i in range(len(portfolio)):
    matrix.append([portfolio[i], index[i]])

Or a one-liner using list comprehension:

matrix2 = [[portfolio[i], index[i]] for i in range(len(portfolio))]

Refresh page after form submitting

<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>"> <!-- notice the updated action -->
<textarea cols="30" rows="4" name="update" id="update" maxlength="200" ></textarea>
<br />
<input name="submit_button" type="submit"  value=" Update "  id="update_button"  class="update_button"/> <!-- notice added name="" -->
</form>

on your full page, you could have this

<?php

// check if the form was submitted
if ($_POST['submit_button']) {
    // this means the submit button was clicked, and the form has refreshed the page
    // to access the content in text area, you would do this
    $a = $_POST['update'];

    // now $a contains the data from the textarea, so you can do whatever with it
    // this will echo the data on the page
    echo $a;
}
else {
    // form not submitted, so show the form

?>

<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>"> <!-- notice the updated action -->
<textarea cols="30" rows="4" name="update" id="update" maxlength="200" ></textarea>
<br />
<input name="submit_button" type="submit"  value=" Update "  id="update_button"  class="update_button"/> <!-- notice added name="" -->
</form>

<?php

} // end "else" loop

?>

CSS centred header image

If you set the margin to be margin:0 auto the image will be centered.

This will give top + bottom a margin of 0, and left and right a margin of 'auto'. Since the div has a width (200px), the image will be 200px wide and the browser will auto set the left and right margin to half of what is left on the page, which will result in the image being centered.

Fully backup a git repo?

Expanding on some other answers, this is what I do:

Setup the repo: git clone --mirror user@server:/url-to-repo.git

Then when you want to refresh the backup: git remote update from the clone location.

This backs up all branches and tags, including new ones that get added later, although it's worth noting that branches that get deleted do not get deleted from the clone (which for a backup may be a good thing).

This is atomic so doesn't have the problems that a simple copy would.

See http://www.garron.me/en/bits/backup-git-bare-repo.html

What is wrong with my SQL here? #1089 - Incorrect prefix key

In PHPMyAdmin, Ignore / leave the size value empty on the pop-up window.

When to use React setState callback

this.setState({
    name:'value' 
},() => {
    console.log(this.state.name);
});

Marker in leaflet, click event

The accepted answer is correct. However, I needed a little bit more clarity, so in case someone else does too:

Leaflet allows events to fire on virtually anything you do on its map, in this case a marker.

So you could create a marker as suggested by the question above:

L.marker([10.496093,-66.881935]).addTo(map).on('mouseover', onClick);

Then create the onClick function:

function onClick(e) {
    alert(this.getLatLng());
}

Now anytime you mouseover that marker it will fire an alert of the current lat/long.

However, you could use 'click', 'dblclick', etc. instead of 'mouseover' and instead of alerting lat/long you can use the body of onClick to do anything else you want:

L.marker([10.496093,-66.881935]).addTo(map).on('click', function(e) {
    console.log(e.latlng);
});

Here is the documentation: http://leafletjs.com/reference.html#events

SQLPLUS error:ORA-12504: TNS:listener was not given the SERVICE_NAME in CONNECT_DATA

I ran into the exact same problem under identical circumstances. I don't have the tnsnames.ora file, and I wanted to use SQL*Plus with Easy Connection Identifier format in command line. I solved this problem as follows.

The SQL*Plus® User's Guide and Reference gives an example:

sqlplus hr@\"sales-server:1521/sales.us.acme.com\"

Pay attention to two important points:

  1. The connection identifier is quoted. You have two options:
    1. You can use SQL*Plus CONNECT command and simply pass quoted string.
    2. If you want to specify connection parameters on the command line then you must add backslashes as shields before quotes. It instructs the bash to pass quotes into SQL*Plus.
  2. The service name must be specified in FQDN-form as it configured by your DBA.

I found these good questions to detect service name via existing connection: 1, 2. Try this query for example:

SELECT value FROM V$SYSTEM_PARAMETER WHERE UPPER(name) = 'SERVICE_NAMES'

Meaning of - <?xml version="1.0" encoding="utf-8"?>

This is the XML optional preamble.

  • version="1.0" means that this is the XML standard this file conforms to
  • encoding="utf-8" means that the file is encoded using the UTF-8 Unicode encoding

can't load package: package .: no buildable Go source files

I had this exact error code and after checking my repository discovered that there were no go files but actually just more directories. So it was more of a red herring than an error for me.

I would recommend doing

go env

and making sure that everything is as it should be, check your environment variables in your OS and check to make sure your shell (bash or w/e ) isn't compromising it via something like a .bash_profile or .bashrc file. good luck.

number of values in a list greater than a certain number

You could do something like this:

>>> j = [4, 5, 6, 7, 1, 3, 7, 5]
>>> sum(i > 5 for i in j)
3

It might initially seem strange to add True to True this way, but I don't think it's unpythonic; after all, bool is a subclass of int in all versions since 2.3:

>>> issubclass(bool, int)
True

How to set entire application in portrait mode only?

You can do it in two ways .

  1. Add android:screenOrientation="portrait" on your manifest file to the corresponding activity
  2. Add setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT); to your activity in `onCreate() method

Removing all unused references from a project in Visual Studio projects

You can try the free VS2010 extension: Reference Assistant by Lardite group. It works perfectly for me. This tool helps to find unused references and allows you to choose which references should be removed.

JSONException: Value of type java.lang.String cannot be converted to JSONObject

The 3 characters at the beginning of your json string correspond to Byte Order Mask (BOM), which is a sequence of Bytes to identify the file as UTF8 file.

Be sure that the file which sends the json is encoded with utf8 (no bom) encoding.

(I had the same issue, with TextWrangler editor. Use save as - utf8 (no bom) to force the right encoding.)

Hope it helps.

Error: The processing instruction target matching "[xX][mM][lL]" is not allowed

Xerces-based tools will emit the following error

The processing instruction target matching "[xX][mM][lL]" is not allowed.

when an XML declaration is encountered anywhere other than at the top of an XML file.

This is a valid diagnostic message; other XML parsers should issue a similar error message in this situation.

To correct the problem, check the following possibilities:

  1. Some blank space or other visible content exists before the <?xml ?> declaration.

    Resolution: remove blank space or any other visible content before the XML declaration.

  2. Some invisible content exists before the <?xml ?> declaration. Most commonly this is a Byte Order Mark (BOM).

    Resolution: Remove the BOM using techniques such as those suggested by the W3C page on the BOM in HTML.

  3. A stray <?xml ?> declaration exists within the XML content. This can happen when XML files are combined programmatically or via cut-and-paste. There can only be one <?xml ?> declaration in an XML file, and it can only be at the top.

    Resolution: Search for <?xml in a case-insensitive manner, and remove all but the top XML declaration from the file.

Parse JSON from HttpURLConnection object

This function will be used get the data from url in form of HttpResponse object.

public HttpResponse getRespose(String url, String your_auth_code){
HttpClient client = new DefaultHttpClient();
HttpPost postForGetMethod = new HttpPost(url);
postForGetMethod.addHeader("Content-type", "Application/JSON");
postForGetMethod.addHeader("Authorization", your_auth_code);
return client.execute(postForGetMethod);
}

Above function is called here and we receive a String form of the json using the Apache library Class.And in following statements we try to make simple pojo out of the json we received.

String jsonString     =     
EntityUtils.toString(getResponse("http://echo.jsontest.com/title/ipsum/content/    blah","Your_auth_if_you_need_one").getEntity(), "UTF-8");
final GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(JsonJavaModel .class, new    CustomJsonDeserialiser());
final Gson gson = gsonBuilder.create();
JsonElement json = new JsonParser().parse(jsonString);
JsonJavaModel pojoModel = gson.fromJson(
                    jsonElementForJavaObject, JsonJavaModel.class);

This is a simple java model class for incomming json. public class JsonJavaModel{ String content; String title; } This is a custom deserialiser:

public class CustomJsonDeserialiserimplements JsonDeserializer<JsonJavaModel>         {

@Override
public JsonJavaModel deserialize(JsonElement json, Type type,
                                 JsonDeserializationContext arg2) throws    JsonParseException {
    final JsonJavaModel jsonJavaModel= new JsonJavaModel();
    JsonObject object = json.getAsJsonObject();

    try {
     jsonJavaModel.content = object.get("Content").getAsString()
     jsonJavaModel.title = object.get("Title").getAsString()

    } catch (Exception e) {

        e.printStackTrace();
    }
    return jsonJavaModel;
}

Include Gson library and org.apache.http.util.EntityUtils;

What does ON [PRIMARY] mean?

To add a very important note on what Mark S. has mentioned in his post. In the specific SQL Script that has been mentioned in the question you can NEVER mention two different file groups for storing your data rows and the index data structure.

The reason why is due to the fact that the index being created in this case is a clustered Index on your primary key column. The clustered index data and the data rows of your table can NEVER be on different file groups.

So in case you have two file groups on your database e.g. PRIMARY and SECONDARY then below mentioned script will store your row data and clustered index data both on PRIMARY file group itself even though I've mentioned a different file group ([SECONDARY]) for the table data. More interestingly the script runs successfully as well (when I was expecting it to give an error as I had given two different file groups :P). SQL Server does the trick behind the scene silently and smartly.

CREATE TABLE [dbo].[be_Categories](
    [CategoryID] [uniqueidentifier] ROWGUIDCOL  NOT NULL CONSTRAINT [DF_be_Categories_CategoryID]  DEFAULT (newid()),
    [CategoryName] [nvarchar](50) NULL,
    [Description] [nvarchar](200) NULL,
    [ParentID] [uniqueidentifier] NULL,
 CONSTRAINT [PK_be_Categories] PRIMARY KEY CLUSTERED 
(
    [CategoryID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [SECONDARY]
GO

NOTE: Your index can reside on a different file group ONLY if the index being created is non-clustered in nature.

The below script which creates a non-clustered index will get created on [SECONDARY] file group instead when the table data already resides on [PRIMARY] file group:

CREATE NONCLUSTERED INDEX [IX_Categories] ON [dbo].[be_Categories]
(
    [CategoryName] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [Secondary]
GO

You can get more information on how storing non-clustered indexes on a different file group can help your queries perform better. Here is one such link.

Is It Possible to NSLog C Structs (Like CGRect or CGPoint)?

I use the following macro to help me out with NSRect:

#define LogRect(RECT) NSLog(@"%s: (%0.0f, %0.0f) %0.0f x %0.0f",
    #RECT, RECT.origin.x, RECT.origin.y, RECT.size.width, RECT.size.height)

You could do something similar for CGPoint:

@define LogCGPoint(POINT) NSLog(@"%s: (%0.0f, %0.0f)",
    #POINT POINT.x, POINT.y);

Using it as follows:

LogCGPoint(cgPoint);

Would produce the following:

cgPoint: (100, 200)

JVM heap parameters

if you wrote: -Xms512m -Xmx512m when it start, java allocate in those moment 512m of ram for his process and cant increment.

-Xms64m -Xmx512m when it start, java allocate only 64m of ram for his process, but java can be increment his memory occupation while 512m.

I think that second thing is better because you give to java the automatic memory management.

Best way to get application folder path

  1. Application.StartupPathand 7. System.IO.Path.GetDirectoryName(Application.ExecutablePath) - Is only going to work for Windows Forms application

  2. System.IO.Path.GetDirectoryName( System.Reflection.Assembly.GetExecutingAssembly().Location)

    Is going to give you something like: "C:\\Windows\\Microsoft.NET\\Framework\\v4.0.30319\\Temporary ASP.NET Files\\legal-services\\e84f415e\\96c98009\\assembly\\dl3\\42aaba80\\bcf9fd83_4b63d101" which is where the page that you are running is.

  3. AppDomain.CurrentDomain.BaseDirectory for web application could be useful and will return something like "C:\\hg\\Services\\Services\\Services.Website\\" which is base directory and is quite useful.

  4. System.IO.Directory.GetCurrentDirectory() and 5. Environment.CurrentDirectory

will get you location of where the process got fired from - so for web app running in debug mode from Visual Studio something like "C:\\Program Files (x86)\\IIS Express"

  1. System.IO.Path.GetDirectoryName( System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase)

will get you location where .dll that is running the code is, for web app that could be "file:\\C:\\hg\\Services\\Services\\Services.Website\\bin"

Now in case of for example console app points 2-6 will be directory where .exe file is.

Hope this saves you some time.

Making heatmap from pandas DataFrame

If you want an interactive heatmap from a Pandas DataFrame and you are running a Jupyter notebook, you can try the interactive Widget Clustergrammer-Widget, see interactive notebook on NBViewer here, documentation here

enter image description here

And for larger datasets you can try the in-development Clustergrammer2 WebGL widget (example notebook here)

How to save python screen output to a text file

I found a quick way for this:

log = open("log.txt", 'a')

def oprint(message):
    print(message)
    global log
    log.write(message)
    return()

code ...

log.close()

Whenever you want to print something just use oprint rather than print.

Note1: In case you want to put the function oprint in a module then import it, use:

import builtins

builtins.log = open("log.txt", 'a')

Note2: what you pass to oprint should be a one string (so if you were using a comma in your print to separate multiple strings, you may replace it with +)

Where's javax.servlet?

The normal procedure with Eclipse and Java EE webapplications is to install a servlet container (Tomcat, Jetty, etc) or application server (Glassfish (which is bundled in the "Sun Java EE" download), JBoss AS, WebSphere, Weblogic, etc) and integrate it in Eclipse using a (builtin) plugin in the Servers view.

During the creation wizard of a new Dynamic Web Project, you can then pick the integrated server from the list. If you happen to have an existing Dynamic Web Project without a server or want to change the associated one, then you need to modify it in the Targeted Rutimes section of the project's properties.

Either way, Eclipse will automatically place the necessary server-specific libraries in the project's classpath (buildpath).

You should absolutely in no way extract and copy server-specific libraries into /WEB-INF/lib or even worse the JRE/lib yourself, to "fix" the compilation errors in Eclipse. It would make your webapplication tied to a specific server and thus completely unportable.

How to convert hex string to Java string?

Using Hex in Apache Commons:

String hexString = "fd00000aa8660b5b010006acdc0100000101000100010000";    
byte[] bytes = Hex.decodeHex(hexString.toCharArray());
System.out.println(new String(bytes, "UTF-8"));

SQL sum with condition

Try moving ValueDate:

select sum(CASE  
             WHEN ValueDate > @startMonthDate THEN cash 
              ELSE 0 
           END) 
 from Table a
where a.branch = p.branch 
  and a.transID = p.transID

(reformatted for clarity)

You might also consider using '0' instead of NULL, as you are doing a sum. It works correctly both ways, but is maybe more indicitive of what your intentions are.

how to display excel sheet in html page

Note that Office Web Components are dead, see does-office-xp-web-components-compatable-with-windows-7. OWC was discontinued from XP onward for security reasons.

Since then, and only recently, Microsoft pushes Excel Web App as alternative (a poor alternative IMHO)

As a side note: Microsoft also deprecated the other way round, i.e. embedding the webbrowser control into an excel sheet, see adding-web-browser-control-to-excel-2013. As an alternative Microsoft offers Office Apps (a very limited alternative with respect to interfacing Excel and IE)

How to compare LocalDate instances Java 8

I believe this snippet will also be helpful in a situation where the dates comparison spans more than two entries.

static final int COMPARE_EARLIEST = 0;

static final int COMPARE_MOST_RECENT = 1;


public LocalDate getTargetDate(List<LocalDate> datesList, int comparatorType) { 
   LocalDate refDate = null;
   switch(comparatorType)
   {
       case COMPARE_EARLIEST:         
       //returns the most earliest of the date entries
          refDate = (LocalDate) datesList.stream().min(Comparator.comparing(item -> 
                      item.toDateTimeAtCurrentTime())).get();
          break;

       case COMPARE_MOST_RECENT:
          //returns the most recent of the date entries 
          refDate = (LocalDate) datesList.stream().max(Comparator.comparing(item -> 
                    item.toDateTimeAtCurrentTime())).get();
          break;
   }

   return refDate;
}

UnicodeEncodeError: 'charmap' codec can't encode characters

In Python 3.7, and running Windows 10 this worked (I am not sure whether it will work on other platforms and/or other versions of Python)

Replacing this line:

with open('filename', 'w') as f:

With this:

with open('filename', 'w', encoding='utf-8') as f:

The reason why it is working is because the encoding is changed to UTF-8 when using the file, so characters in UTF-8 are able to be converted to text, instead of returning an error when it encounters a UTF-8 character that is not suppord by the current encoding.

MySQL - sum column value(s) based on row from the same table

I think you're making this a bit more complicated than it needs to be.

SELECT
    ProductID,
    SUM(IF(PaymentMethod = 'Cash', Amount, 0)) AS 'Cash',
    -- snip
    SUM(Amount) AS Total
FROM
    Payments
WHERE
    SaleDate = '2012-02-10'
GROUP BY
    ProductID

Xcode Objective-C | iOS: delay function / NSTimer help?

[NSTimer scheduledTimerWithTimeInterval:.06 target:self selector:@selector(goToSecondButton:) userInfo:nil repeats:NO];

Is the best one to use. Using sleep(15); will cause the user unable to perform any other actions. With the following function, you would replace goToSecondButton with the appropriate selector or command, which can also be from the frameworks.

Using LINQ to find item in a List but get "Value cannot be null. Parameter name: source"

This error can occur in several places, most commonly running further LINQ queries on top of a null collection. LINQ as Query Syntax can appear more null-safe than it is. Consider the following samples:

var filteredCollection = from item in getMyCollection()
                         orderby item.ReportDate
                         select item;

This code is not NULL SAFE, meaning that if getMyCollection() returns a null, you'll get the Value cannot be null. Parameter name: source error. Very annoying! But it makes perfect sense because LINQ Query syntax is just syntactic sugar for this equivalent code:

var filteredCollection = getMyCollection().OrderBy(x => x.ReportDate);

Which obviously will blow up if the starting method returns a null.

To prevent this, you can use a null coalescing operator in your LINQ query like so:

var filteredCollection = from item in getMyCollection() ?? 
                              Enumerable.Empty<CollectionItemClass>()
                         orderby item.ReportDate
                         select item;

However, you'll have to remember to do this in any related queries. The best approach (if you control the code that generates the collection) is to make it a coding practice to NEVER RETURN A NULL COLLECTION, EVER. In some cases, returning a null object from a method like "getCustomerById(string id)" is fine, depending on your team coding style, but if you have a method that returns a collection of business objects, like "getAllcustomers()" then it should NEVER return a null array/enumerable/etc. Always always always use an if check, the null coalescing operator, or some other switch to return an empty array/list/enumerable etc, so that consumers of your method can freely LINQ over the results.

Get the records of last month in SQL server

SELECT * 
FROM Member
WHERE DATEPART(m, date_created) = DATEPART(m, DATEADD(m, -1, getdate()))
AND DATEPART(yyyy, date_created) = DATEPART(yyyy, DATEADD(m, -1, getdate()))

You need to check the month and year.

Select top 1 result using JPA

Use a native SQL query by specifying a @NamedNativeQuery annotation on the entity class, or by using the EntityManager.createNativeQuery method. You will need to specify the type of the ResultSet using an appropriate class, or use a ResultSet mapping.

javascript: Disable Text Select

For JavaScript use this function:

function disableselect(e) {return false}
document.onselectstart = new Function (return false)
document.onmousedown = disableselect

to enable the selection use this:

function reEnable() {return true}

and use this function anywhere you want:

document.onclick = reEnable

What's the difference between "Solutions Architect" and "Applications Architect"?

There are no industry standard definitions for Architect job titles -- Application/System/Software/Solution Architect all refer in general to a senior developer with strong design and leadership skills. The balance of design, strategy, development (often of core services or frameworks) and management differ based on the organization and project.

The only "Architect" job title that really has a different meaning for me is "Enterprise Architect", which I see as more of a IT strategy position.

MySQL Query to select data from last week?

SELECT id FROM table1
WHERE YEARWEEK(date) = YEARWEEK(NOW() - INTERVAL 1 WEEK)

I use the YEARWEEK function specifically to go back to the prior whole calendar week (as opposed to 7 days before today). YEARWEEK also allows a second argument that will set the start of the week or determine how the first/last week of the year are handled. YEARWEEK lets you to keep the number of weeks to go back/forward in a single variable, and will not include the same week number from prior/future years, and it's far shorter than most of the other answers on here.

How to refresh or show immediately in datagridview after inserting?

Try refreshing the datagrid after each insert

datagridview1.update();
datagridview1.refresh();  

Hope this helps you!

REST API error return good practices

So at first I was tempted to return my application error with 200 OK and a specific XML payload (ie. Pay us more and you'll get the storage you need!) but I stopped to think about it and it seems to soapy (/shrug in horror).

I wouldn't return a 200 unless there really was nothing wrong with the request. From RFC2616, 200 means "the request has succeeded."

If the client's storage quota has been exceeded (for whatever reason), I'd return a 403 (Forbidden):

The server understood the request, but is refusing to fulfill it. Authorization will not help and the request SHOULD NOT be repeated. If the request method was not HEAD and the server wishes to make public why the request has not been fulfilled, it SHOULD describe the reason for the refusal in the entity. If the server does not wish to make this information available to the client, the status code 404 (Not Found) can be used instead.

This tells the client that the request was OK, but that it failed (something a 200 doesn't do). This also gives you the opportunity to explain the problem (and its solution) in the response body.

What other specific error conditions did you have in mind?

What is the difference between MOV and LEA?

If you only specify a literal, there is no difference. LEA has more abilities, though, and you can read about them here:

http://www.oopweb.com/Assembly/Documents/ArtOfAssembly/Volume/Chapter_6/CH06-1.html#HEADING1-136

Search text in fields in every table of a MySQL database

This solution
a) is only MySQL, no other language needed, and
b) returns SQL results, ready for processing!

#Search multiple database tables and/or columns
#Version 0.1 - JK 2014-01
#USAGE: 1. set the search term @search, 2. set the scope by adapting the WHERE clause of the `information_schema`.`columns` query
#NOTE: This is a usage example and might be advanced by setting the scope through a variable, putting it all in a function, and so on...

#define the search term here (using rules for the LIKE command, e.g % as a wildcard)
SET @search = '%needle%';

#settings
SET SESSION group_concat_max_len := @@max_allowed_packet;

#ini variable
SET @sql = NULL;

#query for prepared statement
SELECT
    GROUP_CONCAT("SELECT '",`TABLE_NAME`,"' AS `table`, '",`COLUMN_NAME`,"' AS `column`, `",`COLUMN_NAME`,"` AS `value` FROM `",TABLE_NAME,"` WHERE `",COLUMN_NAME,"` LIKE '",@search,"'" SEPARATOR "\nUNION\n") AS col
INTO @sql
FROM `information_schema`.`columns`
WHERE TABLE_NAME IN
(
    SELECT TABLE_NAME FROM `information_schema`.`columns`
    WHERE
        TABLE_SCHEMA IN ("my_database")
        && TABLE_NAME IN ("my_table1", "my_table2") || TABLE_NAME LIKE "my_prefix_%"
);

#prepare and execute the statement
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

Return Type for jdbcTemplate.queryForList(sql, object, classType)

List<Map<String, Object>> List = getJdbcTemplate().queryForList(SELECT_ALL_CONVERSATIONS_SQL_FULL, new Object[] {userId, dateFrom, dateTo});
for (Map<String, Object> rowMap : resultList) {
    DTO dTO = new DTO();
    dTO.setrarchyID((Long) (rowMap.get("ID")));
}

jQuery remove all list items from an unordered list

$("ul").empty() works fine. Is there some other error?

_x000D_
_x000D_
$('input').click(function() {_x000D_
  $('ul').empty()_x000D_
});
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
<ul>_x000D_
  <li>test</li>_x000D_
  <li>test</li>_x000D_
</ul>_x000D_
_x000D_
<input type="button" value="click me" />
_x000D_
_x000D_
_x000D_

http://jsfiddle.net/infernalbadger/D5ss8/

Autoresize View When SubViews are Added

Yes, it is because you are using auto layout. Setting the view frame and resizing mask will not work.

You should read Working with Auto Layout Programmatically and Visual Format Language.

You will need to get the current constraints, add the text field, adjust the contraints for the text field, then add the correct constraints on the text field.

Confused about Service vs Factory

Service style: (probably the simplest one) returns the actual function: Useful for sharing utility functions that are useful to invoke by simply appending () to the injected function reference.

A service in AngularJS is a singleton JavaScript object which contains a set of functions

var myModule = angular.module("myModule", []);

myModule.value  ("myValue"  , "12345");

function MyService(myValue) {
    this.doIt = function() {
        console.log("done: " + myValue;
    }
}

myModule.service("myService", MyService);
myModule.controller("MyController", function($scope, myService) {

    myService.doIt();

});

Factory style: (more involved but more sophisticated) returns the function's return value: instantiate an object like new Object() in java.

Factory is a function that creates values. When a service, controller etc. needs a value injected from a factory, the factory creates the value on demand. Once created, the value is reused for all services, controllers etc. which need it injected.

var myModule = angular.module("myModule", []);

myModule.value("numberValue", 999);

myModule.factory("myFactory", function(numberValue) {
    return "a value: " + numberValue;
})  
myModule.controller("MyController", function($scope, myFactory) {

    console.log(myFactory);

});

Provider style: (full blown, configurable version) returns the output of the function's $get function: Configurable.

Providers in AngularJS is the most flexible form of factory you can create. You register a provider with a module just like you do with a service or factory, except you use the provider() function instead.

var myModule = angular.module("myModule", []);

myModule.provider("mySecondService", function() {
    var provider = {};
    var config   = { configParam : "default" };

    provider.doConfig = function(configParam) {
        config.configParam = configParam;
    }

    provider.$get = function() {
        var service = {};

        service.doService = function() {
            console.log("mySecondService: " + config.configParam);
        }

        return service;
    }

    return provider;
});

myModule.config( function( mySecondServiceProvider ) {
    mySecondServiceProvider.doConfig("new config param");
});

myModule.controller("MyController", function($scope, mySecondService) {

    $scope.whenButtonClicked = function() {
        mySecondService.doIt();
    }

});

src jenkov

_x000D_
_x000D_
<!DOCTYPE html>_x000D_
    <html ng-app="app">_x000D_
    <head>_x000D_
     <script src="http://cdnjs.cloudflare.com/ajax/libs/angular.js/1.0.1/angular.min.js"></script>_x000D_
     <meta charset=utf-8 />_x000D_
     <title>JS Bin</title>_x000D_
    </head>_x000D_
    <body ng-controller="MyCtrl">_x000D_
     {{serviceOutput}}_x000D_
     <br/><br/>_x000D_
     {{factoryOutput}}_x000D_
     <br/><br/>_x000D_
     {{providerOutput}}_x000D_
    _x000D_
     <script>_x000D_
    _x000D_
      var app = angular.module( 'app', [] );_x000D_
    _x000D_
      var MyFunc = function() {_x000D_
    _x000D_
       this.name = "default name";_x000D_
    _x000D_
       this.$get = function() {_x000D_
        this.name = "new name"_x000D_
        return "Hello from MyFunc.$get(). this.name = " + this.name;_x000D_
       };_x000D_
    _x000D_
       return "Hello from MyFunc(). this.name = " + this.name;_x000D_
      };_x000D_
    _x000D_
      // returns the actual function_x000D_
      app.service( 'myService', MyFunc );_x000D_
    _x000D_
      // returns the function's return value_x000D_
      app.factory( 'myFactory', MyFunc );_x000D_
    _x000D_
      // returns the output of the function's $get function_x000D_
      app.provider( 'myProv', MyFunc );_x000D_
    _x000D_
      function MyCtrl( $scope, myService, myFactory, myProv ) {_x000D_
    _x000D_
       $scope.serviceOutput = "myService = " + myService;_x000D_
       $scope.factoryOutput = "myFactory = " + myFactory;_x000D_
       $scope.providerOutput = "myProvider = " + myProv;_x000D_
    _x000D_
      }_x000D_
    _x000D_
     </script>_x000D_
    _x000D_
    </body>_x000D_
    </html>
_x000D_
_x000D_
_x000D_

jsbin

_x000D_
_x000D_
<!DOCTYPE html>_x000D_
<html ng-app="myApp">_x000D_
<head>_x000D_
 <script src="http://cdnjs.cloudflare.com/ajax/libs/angular.js/1.0.1/angular.min.js"></script>_x000D_
 <meta charset=utf-8 />_x000D_
 <title>JS Bin</title>_x000D_
</head>_x000D_
<body>_x000D_
<div ng-controller="MyCtrl">_x000D_
    {{hellos}}_x000D_
</div>_x000D_
 <script>_x000D_
_x000D_
 var myApp = angular.module('myApp', []);_x000D_
_x000D_
//service style, probably the simplest one_x000D_
myApp.service('helloWorldFromService', function() {_x000D_
    this.sayHello = function() {_x000D_
        return "Hello, World!"_x000D_
    };_x000D_
});_x000D_
_x000D_
//factory style, more involved but more sophisticated_x000D_
myApp.factory('helloWorldFromFactory', function() {_x000D_
    return {_x000D_
        sayHello: function() {_x000D_
            return "Hello, World!"_x000D_
        }_x000D_
    };_x000D_
});_x000D_
    _x000D_
//provider style, full blown, configurable version     _x000D_
myApp.provider('helloWorld', function() {_x000D_
_x000D_
    this.name = 'Default';_x000D_
_x000D_
    this.$get = function() {_x000D_
        var name = this.name;_x000D_
        return {_x000D_
            sayHello: function() {_x000D_
                return "Hello, " + name + "!"_x000D_
            }_x000D_
        }_x000D_
    };_x000D_
_x000D_
    this.setName = function(name) {_x000D_
        this.name = name;_x000D_
    };_x000D_
});_x000D_
_x000D_
//hey, we can configure a provider!            _x000D_
myApp.config(function(helloWorldProvider){_x000D_
    helloWorldProvider.setName('World');_x000D_
});_x000D_
        _x000D_
_x000D_
function MyCtrl($scope, helloWorld, helloWorldFromFactory, helloWorldFromService) {_x000D_
    _x000D_
    $scope.hellos = [_x000D_
        helloWorld.sayHello(),_x000D_
        helloWorldFromFactory.sayHello(),_x000D_
        helloWorldFromService.sayHello()];_x000D_
}_x000D_
 </script>_x000D_
_x000D_
</body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

jsfiddle

Python write line by line to a text file

Well, the problem you have is wrong line ending/encoding for notepad. Notepad uses Windows' line endings - \r\n and you use \n.

Convert INT to VARCHAR SQL

Actually you don't need to use STR Or Convert. Just select 'xxx'+LTRIM(ColumnName) does the job. Possibly, LTRIM uses Convert or STR under the hood.

LTRIM also removes need for providing length and usually default 10 is good enough for integer to string conversion.

SELECT LTRIM(ColumnName) FROM TableName

Convert datetime to valid JavaScript date

Just use Date.parse() which returns a Number, then use new Date() to parse it:

var thedate = new Date(Date.parse("2011-07-14 11:23:00"));

Center the nav in Twitter Bootstrap

I prefer this :

<nav class="navbar">
  <div class="hidden-xs hidden-sm" style="position: absolute;left: 50%;margin-left:-56px;width:112px" id="centered-div">
    <!-- this element is on the center of the nav, visible only on -md and -lg -->
    <a></a>
  </div>

  <div class="container-fluid">
    <!-- ...things with your navbar... -->
      <div class="visible-xs visible-sm">
        <!-- this element will be hidden on -md and -lg -->
      </div>
    <!-- ...things with your navbar... -->
  </div>
</nav>

The element is perfectly centered, and will be hidden on some screen sizes (there was no place left on -xs and -sm for me for example). I get the idea from Twitter's actual navbar

Python - Module Not Found

I had same error. For those who run python scripts on different servers, please check if the python path is correctly specified in shebang. For me on each server it was located in different dirs.

How do I make Java register a string input with spaces?

Instead of

Scanner in = new Scanner(System.in);
String question;
question = in.next();

Type in

Scanner in = new Scanner(System.in);
String question;
question = in.nextLine();

This should be able to take spaces as input.

How to make the main content div fill height of screen with css

There is a CSS unit called viewport height / viewport width.

Example

.mainbody{height: 100vh;} similarly html,body{width: 100vw;}

or 90vh = 90% of the viewport height.

**IE9+ and most modern browsers.

How to check if a subclass is an instance of a class at runtime?

If there is polymorphism such as checking SQLRecoverableException vs SQLException, it can be done like that.

try {
    // sth may throw exception
    ....
} catch (Exception e) {
    if(SQLException.class.isAssignableFrom(e.getCause().getClass()))
    {
        // do sth
        System.out.println("SQLException occurs!");
    }
}

Simply say,

ChildClass child= new ChildClass();
if(ParentClass.class.isAssignableFrom(child.getClass()))
{
    // do sth
    ...
}

How to deal with bad_alloc in C++?

You can catch it like any other exception:

try {
  foo();
}
catch (const std::bad_alloc&) {
  return -1;
}

Quite what you can usefully do from this point is up to you, but it's definitely feasible technically.



In general you cannot, and should not try, to respond to this error. bad_alloc indicates that a resource cannot be allocated because not enough memory is available. In most scenarios your program cannot hope to cope with that, and terminating soon is the only meaningful behaviour.

Worse, modern operating systems often over-allocate: on such systems, malloc and new can return a valid pointer even if there is not enough free memory left – std::bad_alloc will never be thrown, or is at least not a reliable sign of memory exhaustion. Instead, attempts to access the allocated memory will then result in a segmentation fault, which is not catchable (you can handle the segmentation fault signal, but you cannot resume the program afterwards).

The only thing you could do when catching std::bad_alloc is to perhaps log the error, and try to ensure a safe program termination by freeing outstanding resources (but this is done automatically in the normal course of stack unwinding after the error gets thrown if the program uses RAII appropriately).

In certain cases, the program may attempt to free some memory and try again, or use secondary memory (= disk) instead of RAM but these opportunities only exist in very specific scenarios with strict conditions:

  1. The application must ensure that it runs on a system that does not overcommit memory, i.e. it signals failure upon allocation rather than later.
  2. The application must be able to free memory immediately, without any further accidental allocations in the meantime.

It’s exceedingly rare that applications have control over point 1 — userspace applications never do, it’s a system-wide setting that requires root permissions to change.1

OK, so let’s assume you’ve fixed point 1. What you can now do is for instance use a LRU cache for some of your data (probably some particularly large business objects that can be regenerated or reloaded on demand). Next, you need to put the actual logic that may fail into a function that supports retry — in other words, if it gets aborted, you can just relaunch it:

lru_cache<widget> widget_cache;

double perform_operation(int widget_id) {
    std::optional<widget> maybe_widget = widget_cache.find_by_id(widget_id);
    if (not maybe_widget) {
        maybe_widget = widget_cache.store(widget_id, load_widget_from_disk(widget_id));
    }
    return maybe_widget->frobnicate();
}

…

for (int num_attempts = 0; num_attempts < MAX_NUM_ATTEMPTS; ++num_attempts) {
    try {
        return perform_operation(widget_id);
    } catch (std::bad_alloc const&) {
        if (widget_cache.empty()) throw; // memory error elsewhere.
        widget_cache.remove_oldest();
    }
}

// Handle too many failed attempts here.

But even here, using std::set_new_handler instead of handling std::bad_alloc provides the same benefit and would be much simpler.


1 If you’re creating an application that does control point 1, and you’re reading this answer, please shoot me an email, I’m genuinely curious about your circumstances.


What is the C++ Standard specified behavior of new in c++?

The usual notion is that if new operator cannot allocate dynamic memory of the requested size, then it should throw an exception of type std::bad_alloc.
However, something more happens even before a bad_alloc exception is thrown:

C++03 Section 3.7.4.1.3: says

An allocation function that fails to allocate storage can invoke the currently installed new_handler(18.4.2.2), if any. [Note: A program-supplied allocation function can obtain the address of the currently installed new_handler using the set_new_handler function (18.4.2.3).] If an allocation function declared with an empty exception-specification (15.4), throw(), fails to allocate storage, it shall return a null pointer. Any other allocation function that fails to allocate storage shall only indicate failure by throw-ing an exception of class std::bad_alloc (18.4.2.1) or a class derived from std::bad_alloc.

Consider the following code sample:

#include <iostream>
#include <cstdlib>

// function to call if operator new can't allocate enough memory or error arises
void outOfMemHandler()
{
    std::cerr << "Unable to satisfy request for memory\n";

    std::abort();
}

int main()
{
    //set the new_handler
    std::set_new_handler(outOfMemHandler);

    //Request huge memory size, that will cause ::operator new to fail
    int *pBigDataArray = new int[100000000L];

    return 0;
}

In the above example, operator new (most likely) will be unable to allocate space for 100,000,000 integers, and the function outOfMemHandler() will be called, and the program will abort after issuing an error message.

As seen here the default behavior of new operator when unable to fulfill a memory request, is to call the new-handler function repeatedly until it can find enough memory or there is no more new handlers. In the above example, unless we call std::abort(), outOfMemHandler() would be called repeatedly. Therefore, the handler should either ensure that the next allocation succeeds, or register another handler, or register no handler, or not return (i.e. terminate the program). If there is no new handler and the allocation fails, the operator will throw an exception.

What is the new_handler and set_new_handler?

new_handler is a typedef for a pointer to a function that takes and returns nothing, and set_new_handler is a function that takes and returns a new_handler.

Something like:

typedef void (*new_handler)();
new_handler set_new_handler(new_handler p) throw();

set_new_handler's parameter is a pointer to the function operator new should call if it can't allocate the requested memory. Its return value is a pointer to the previously registered handler function, or null if there was no previous handler.

How to handle out of memory conditions in C++?

Given the behavior of newa well designed user program should handle out of memory conditions by providing a proper new_handlerwhich does one of the following:

Make more memory available: This may allow the next memory allocation attempt inside operator new's loop to succeed. One way to implement this is to allocate a large block of memory at program start-up, then release it for use in the program the first time the new-handler is invoked.

Install a different new-handler: If the current new-handler can't make any more memory available, and of there is another new-handler that can, then the current new-handler can install the other new-handler in its place (by calling set_new_handler). The next time operator new calls the new-handler function, it will get the one most recently installed.

(A variation on this theme is for a new-handler to modify its own behavior, so the next time it's invoked, it does something different. One way to achieve this is to have the new-handler modify static, namespace-specific, or global data that affects the new-handler's behavior.)

Uninstall the new-handler: This is done by passing a null pointer to set_new_handler. With no new-handler installed, operator new will throw an exception ((convertible to) std::bad_alloc) when memory allocation is unsuccessful.

Throw an exception convertible to std::bad_alloc. Such exceptions are not be caught by operator new, but will propagate to the site originating the request for memory.

Not return: By calling abort or exit.

How to link C++ program with Boost using CMake

Adapting @MOnsDaR answer for modern CMake syntax with imported targets, this would be:

find_package(Boost 1.40 COMPONENTS program_options REQUIRED)

add_executable(anyExecutable myMain.cpp)

target_link_libraries(anyExecutable Boost::program_options)

Note that it is not necessary to specify the include directories manually, since it is already taken care of through the imported target Boost::program_options.

How to solve "java.io.IOException: error=12, Cannot allocate memory" calling Runtime#exec()?

This is the solution but you have to set:

echo 1 > /proc/sys/vm/overcommit_memory

Image Processing: Algorithm Improvement for 'Coca-Cola Can' Recognition

You need a program that learns and improves classification accuracy organically from experience.

I'll suggest deep learning, with deep learning this becomes a trivial problem.

You can retrain the inception v3 model on Tensorflow:

How to Retrain Inception's Final Layer for New Categories.

In this case, you will be training a convolutional neural network to classify an object as either a coca-cola can or not.

How to update value of a key in dictionary in c#?

Dictionary is a key value pair. Catch Key by

dic["cat"] 

and assign its value like

dic["cat"] = 5

How to find the files that are created in the last hour in unix

check out this link and then help yourself out.

the basic code is

#create a temp. file
echo "hi " >  t.tmp
# set the file time to 2 hours ago
touch -t 200405121120  t.tmp 
# then check for files
find /admin//dump -type f  -newer t.tmp -print -exec ls -lt {} \; | pg

Conditional formatting, entire row based

Use RC addressing. So, if I want the background color of Col B to depend upon the value in Col C and apply that from Rows 2 though 20:

Steps:

  1. Select R2C2 to R20C2

  2. Click on Conditional Formatting

  3. Select "Use a formula to determine what cells to format"

  4. Type in the formula: =RC[1] > 25

  5. Create the formatting you want (i.e. background color "yellow")

  6. Applies to: Make sure it says: =R2C2:R20C2

** Note that the "magic" takes place in step 4 ... using RC addressing to look at the value one column to the right of the cell being formatted. In this example, I am checking to see if the value of the cell one column to the right of the cell being formatting contains a value greater than 25 (note that you can put pretty much any formula here that returns a T/F value)

Enable vertical scrolling on textarea

Try this: http://jsfiddle.net/8fv6e/8/

It is another version of the answers.

HTML:

<label for="aboutDescription" id="aboutHeading">About</label>
<textarea rows="15" cols="50" id="aboutDescription"
    style="max-height:100px;min-height:100px; resize: none"></textarea>
<a  id="imageURLId" target="_blank">Go to
    HomePage</a>

CSS:

#imageURLId{
font-size: 14px;
font-weight: normal;
resize: none;
overflow-y: scroll;

}

Angular2 *ngIf check object array length in template

You could use *ngIf="teamMembers != 0" to check whether data is present

How to put space character into a string name in XML?

If you are trying to give Space Between 2 string OR In String file of android then do this in your string file . Implement this before your "String name" that you want to show. \u0020\u0020 For E.g.. \u0020\u0020\u0020\u0020\u0020\u0020Payment

Python + Regex: AttributeError: 'NoneType' object has no attribute 'groups'

import re

htmlString = '</dd><dt> Fine, thank you.&#160;</dt><dd> Molt bé, gràcies. (<i>mohl behh, GRAH-syuhs</i>)'

SearchStr = '(\<\/dd\>\<dt\>)+ ([\w+\,\.\s]+)([\&\#\d\;]+)(\<\/dt\>\<dd\>)+ ([\w\,\s\w\s\w\?\!\.]+) (\(\<i\>)([\w\s\,\-]+)(\<\/i\>\))'

Result = re.search(SearchStr.decode('utf-8'), htmlString.decode('utf-8'), re.I | re.U)

print Result.groups()

Works that way. The expression contains non-latin characters, so it usually fails. You've got to decode into Unicode and use re.U (Unicode) flag.

I'm a beginner too and I faced that issue a couple of times myself.

Laravel 5 PDOException Could Not Find Driver

It will depend of your php version. Check it running:

php -version

Now, according to your current version, run:

sudo apt-get install php7.2-mysql

Extension methods must be defined in a non-generic static class

A work-around for people who are experiencing a bug like Nathan:

The on-the-fly compiler seems to have a problem with this Extension Method error... adding static didn't help me either.

I'd like to know what causes the bug?

But the work-around is to write a new Extension class (not nested) even in same file and re-build.

Figured that this thread is getting enough views that it's worth passing on (the limited) solution I found. Most people probably tried adding 'static' before google-ing for a solution! and I didn't see this work-around fix anywhere else.

Can I bind an array to an IN() condition?

For something quick:

//$db = new PDO(...);
//$ids = array(...);

$qMarks = str_repeat('?,', count($ids) - 1) . '?';
$sth = $db->prepare("SELECT * FROM myTable WHERE id IN ($qMarks)");
$sth->execute($ids);

Difference between MEAN.js and MEAN.io

They're essentially the same... They both use swig for templating, they both use karma and mocha for tests, passport integration, nodemon, etc.

Why so similar? Mean.js is a fork of Mean.io and both initiatives were started by the same guy... Mean.io is now under the umbrella of the company Linnovate and looks like the guy (Amos Haviv) stopped his collaboration with this company and started Mean.js. You can read more about the reasons here.

Now... main (or little) differences you can see right now are:


SCAFFOLDING AND BOILERPLATE GENERATION

Mean.io uses a custom cli tool named 'mean'
Mean.js uses Yeoman Generators


MODULARITY

Mean.io uses a more self-contained node packages modularity with client and server files inside the modules.
Mean.js uses modules just in the front-end (for angular), and connects them with Express. Although they were working on vertical modules as well...


BUILD SYSTEM

Mean.io has recently moved to gulp
Mean.js uses grunt


DEPLOYMENT

Both have Dockerfiles in their respective repos, and Mean.io has one-click install on Google Compute Engine, while Mean.js can also be deployed with one-click install on Digital Ocean.


DOCUMENTATION

Mean.io has ok docs
Mean.js has AWESOME docs


COMMUNITY

Mean.io has a bigger community since it was the original boilerplate
Mean.js has less momentum but steady growth


On a personal level, I like more the philosophy and openness of MeanJS and more the traction and modules/packages approach of MeanIO. Both are nice, and you'll end probably modifying them, so you can't really go wrong picking one or the other. Just take them as starting point and as a learning exercise.


ALTERNATIVE “MEAN” SOLUTIONS

MEAN is a generic way (coined by Valeri Karpov) to describe a boilerplate/framework that takes "Mongo + Express + Angular + Node" as the base of the stack. You can find frameworks with this stack that use other denomination, some of them really good for RAD (Rapid Application Development) and building SPAs. Eg:

You also have Hackathon Starter. It doesn't have A of MEAN (it is 'MEN'), but it rocks..

Have fun!

Print values for multiple variables on the same line from within a for-loop

As an additional note, there is no need for the for loop because of R's vectorization.

This:

P <- 243.51
t <- 31 / 365
n <- 365

for (r in seq(0.15, 0.22, by = 0.01))    
     A <- P * ((1 + (r/ n))^ (n * t))
     interest <- A - P
}

is equivalent to:

P <- 243.51
t <- 31 / 365
n <- 365
r <- seq(0.15, 0.22, by = 0.01)
A <- P * ((1 + (r/ n))^ (n * t))
interest <- A - P

Because r is a vector, the expression above containing it is performed for all values of the vector.