Programs & Examples On #Ucma

Unified Communications Managed API (UCMA)

How to save a data frame as CSV to a user selected location using tcltk

write.csv([enter name of dataframe here],file = file.choose(new = T))

After running above script this window will open :

enter image description here

Type the new file name with extension in the File name field and click Open, it'll ask you to create a new file to which you should select Yes and the file will be created and saved in the desired location.

how to mysqldump remote db from local machine

One can invoke mysqldump locally against a remote server.

Example that worked for me:

mysqldump -h hostname-of-the-server -u mysql_user -p database_name > file.sql

I followed the mysqldump documentation on connection options.

How to cast or convert an unsigned int to int in C?

Unsigned int can be converted to signed (or vice-versa) by simple expression as shown below :

unsigned int z;
int y=5;
z= (unsigned int)y;   

Though not targeted to the question, you would like to read following links :

How to add Headers on RESTful call using Jersey Client API

Try this!

Client client = ClientBuilder.newClient();

String jsonStr = client

            .header("WM_SVC.NAME", "RegistryService")
            .header("WM_QOS.CORRELATION_ID", "d1f0c0d2-2cf4-497b-b630-06d609d987b0")


P.S You can add any number of headers like this!

What is the difference between supervised learning and unsupervised learning?

In Supervised Learning we know what the input and output should be. For example , given a set of cars. We have to find out which ones red and which ones blue.

Whereas, Unsupervised learning is where we have to find out the answer with a very little or without any idea about how the output should be. For example, a learner might be able to build a model that detects when people are smiling based on correlation of facial patterns and words such as "what are you smiling about?".

select2 onchange event only works once

As of version 4.0.0, events such as select2-selecting, no longer work. They are renamed as follows:

  • select2-close is now select2:close
  • select2-open is now select2:open
  • select2-opening is now select2:opening
  • select2-selecting is now select2:selecting
  • select2-removed is now select2:removed
  • select2-removing is now select2:unselecting


  $('.select2').on('select2:selecting', function(e) {_x000D_
    console.log('Selecting: ' ,;_x000D_
  font-family: sans-serif;_x000D_
  width: 100%;_x000D_
<link href="" rel="stylesheet">_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<select class="select2" multiple="multiple">_x000D_
  <option value="1">Option 1</option>_x000D_
  <option value="2">Option 2</option>_x000D_
  <option value="3">Option 3</option>_x000D_
  <option value="4">Option 4</option>_x000D_
  <option value="5">Option 5</option>_x000D_
  <option value="6">Option 6</option>_x000D_
  <option value="7">Option 7</option>_x000D_

Java: print contents of text file to screen

For those new to Java and wondering why Jiri's answer doesn't work, make sure you do what he says and handle the exception or else it won't compile. Here's the bare minimum:


public class ReadFile {

    public static void main(String args[]) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader("test.txt"));
        for (String line; (line = br.readLine()) != null;) {

How to access private data members outside the class without making "friend"s?

access private members outside class ....only for study purpose .... This program accepts all the below conditions "I dont want to create member function for above class A. And also i dont want to inherit the above class A. I dont want to change the specifier of iData."

//here member function is used only to input and output the private values ... //void hack() is defined outside the class...

//GEEK MODE....;)

    class A
    private :int iData,x;
    public: void get()             //enter the values
        {cout<<"Enter iData : ";
            cin>>iData;cout<<"Enter x : ";cin>>x;}

        void put()                               //displaying values
    {cout<<endl<<"sum = "<<iData+x;}

void hack();        //hacking function

void main()
{A obj;clrscr();

void hack()         //hack begins
{int hck,*ptr=&hck;
cout<<endl<<"Enter value of private data (iData or x) : ";
cin>>hck;     //enter the value assigned for iData or x
for(int i=0;i<5;i++)
{cout<<"Private data hacked...!!!\nChange the value : ";
cin>>*ptr;cout<<hck<<" Is chaged to : "<<*ptr;
}cout<<"Sorry value not found.....";

Excel Define a range based on a cell value

You can also use OFFSET:


It moves the range $A$10 up by $B$1-1 (becomes $A$6 ($A$5)) and then resizes the range to $B$1 rows (becomes $A$6:$A$10 ($A$5:$A$10))

Is it possible to include one CSS file in another?


@import url("base.css");


  • The @import rule must precede all other rules (except @charset).
  • Additional @import statements require additional server requests. As an alternative, concatenate all CSS into one file to avoid multiple HTTP requests. For example, copy the contents of base.css and special.css into base-special.css and reference only base-special.css.

C error: undefined reference to function, but it IS defined

Add the "extern" keyword to the function definitions in point.h

Convert pandas timezone-aware DateTimeIndex to naive timestamp, but in certain timezone

Setting the tz attribute of the index explicitly seems to work:

ts_utc = ts.tz_convert("UTC") = None

Java: Simplest way to get last word in a string

Get the last word in Kotlin:

String.substringAfterLast(" ")

lambda expression join multiple tables with select and where clause

If I understand your questions correctly, all you need to do is add the .Where(m => m.r.u.UserId == 1):

    var UserInRole = db.UserProfiles.
        Join(db.UsersInRoles, u => u.UserId, uir => uir.UserId,
        (u, uir) => new { u, uir }).
        Join(db.Roles, r => r.uir.RoleId, ro => ro.RoleId, (r, ro) => new { r, ro })
        .Where(m => m.r.u.UserId == 1)
        .Select (m => new AddUserToRole
            UserName = m.r.u.UserName,
            RoleName =

Hope that helps.

How to convert an Instant to a date format?

Instant i = Instant.ofEpochSecond(cal.getTime);

Read more here and here

Rounded corners for <input type='text' /> using for IE

Writing from phone, but curvycorners is really good, since it adds it's own borders only if browser doesn't support it by default. In other words, browsers which already support some CSS3 will use their own system to provide corners.

Cross domain POST request is not sending cookie Ajax Jquery

Please note this doesn't solve the cookie sharing process, as in general this is bad practice.

You need to be using JSONP as your type:

From $.ajax documentation: Cross-domain requests and dataType: "jsonp" requests do not support synchronous operation.

      type: "POST",
      url: "",
      dataType: 'jsonp',
      xhrFields: {
           withCredentials: true
      crossDomain: true,
      beforeSend: function(xhr) {
            xhr.setRequestHeader("Cookie", "session=xxxyyyzzz");
      success: function(){
      error: function (xhr) {

C# - How to get Program Files (x86) on Windows 64 bit

The function below will return the x86 Program Files directory in all of these three Windows configurations:

  • 32 bit Windows
  • 32 bit program running on 64 bit Windows
  • 64 bit program running on 64 bit windows


static string ProgramFilesx86()
    if( 8 == IntPtr.Size 
        || (!String.IsNullOrEmpty(Environment.GetEnvironmentVariable("PROCESSOR_ARCHITEW6432"))))
        return Environment.GetEnvironmentVariable("ProgramFiles(x86)");

    return Environment.GetEnvironmentVariable("ProgramFiles");

How to check if an integer is in a given range?


if (i>0 && i<100) {} 

it will work at least ;)

Maven:Failed to execute goal org.apache.maven.plugins:maven-resources-plugin:2.7:resources



Was getting the following exception:

Caused by: org.apache.maven.plugin.MojoExecutionException: Mark invalid
    at org.apache.maven.plugin.resources.ResourcesMojo.execute(
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(
    ... 25 more
Caused by: org.apache.maven.shared.filtering.MavenFilteringException: Mark invalid
    at org.apache.maven.shared.filtering.DefaultMavenFileFilter.copyFile(
    at org.apache.maven.shared.filtering.DefaultMavenResourcesFiltering.filterResources(
    at org.apache.maven.plugin.resources.ResourcesMojo.execute(
    ... 27 more
Caused by: Mark invalid
    at org.apache.maven.shared.filtering.DefaultMavenFileFilter.copyFile(
    ... 29 more

Then it is gone after adding maven-filtering 1.3:


angular.service vs angular.factory

I have spent some time trying to figure out the difference.

And i think the factory function uses the module pattern and service function uses the standard java script constructor pattern.

Should I return EXIT_SUCCESS or 0 from main()?

Once you start writing code that can return a myriad of exit statuses, you start #define'ing all of them. In this case EXIT_SUCCESS makes sense in context of not being a "magic number". This makes your code more readable because every other exit code will be EXIT_SOMETHING. If you simply write a program that will return when it's done, return 0 is valid, and probably even cleaner because it suggests that there's no sophisticated return code structure.

How to save a base64 image to user's disk using JavaScript?

HTML5 download attribute

Just to allow user to download the image or other file you may use the HTML5 download attribute.

Static file download

<a href="/images/image-name.jpg" download>
<!-- OR -->
<a href="/images/image-name.jpg" download="new-image-name.jpg"> 

Dynamic file download

In cases requesting image dynamically it is possible to emulate such download.

If your image is already loaded and you have the base64 source then:

function saveBase64AsFile(base64, fileName) {
    var link = document.createElement("a");

    document.body.appendChild(link); // for Firefox

    link.setAttribute("href", base64);
    link.setAttribute("download", fileName);;

Otherwise if image file is downloaded as Blob you can use FileReader to convert it to Base64:

function saveBlobAsFile(blob, fileName) {
    var reader = new FileReader();

    reader.onloadend = function () {    
        var base64 = reader.result ;
        var link = document.createElement("a");

        document.body.appendChild(link); // for Firefox

        link.setAttribute("href", base64);
        link.setAttribute("download", fileName);;



The anchor tag you are creating also needs to be added to the DOM in Firefox, in order to be recognized for click events (Link).

IE is not supported: Caniuse link

How to grep and replace

I got the answer.

grep -rl matchstring somedir/ | xargs sed -i 's/string1/string2/g'

How does Facebook disable the browser's integrated Developer Tools?

I located the Facebook's console buster script using Chrome developer tools. Here is the script with minor changes for readability. I have removed the bits that I could not understand:

Object.defineProperty(window, "console", {
    value: console,
    writable: false,
    configurable: false

var i = 0;
function showWarningAndThrow() {
    if (!i) {
        setTimeout(function () {
            console.log("%cWarning message", "font: 2em sans-serif; color: yellow; background-color: red;");
        }, 1);
        i = 1;
    throw "Console is disabled";

var l, n = {
        set: function (o) {
            l = o;
        get: function () {
            return l;
Object.defineProperty(console, "_commandLineAPI", n);
Object.defineProperty(console, "__commandLineAPI", n);

With this, the console auto-complete fails silently while statements typed in console will fail to execute (the exception will be logged).


startForeground fail after upgrade to Android 8.1

Here is my solution

private static final int NOTIFICATION_ID = 200;
private static final String CHANNEL_ID = "myChannel";
private static final String CHANNEL_NAME = "myChannelName";

private void startForeground() {

    final NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(
            getApplicationContext(), CHANNEL_ID);

    Notification notification;

        notification = mBuilder.setTicker(getString(R.string.app_name)).setWhen(0)
                .setContentText("Send SMS gateway is running background")

        NotificationManager notificationManager = (NotificationManager) getApplication().getSystemService(Context.NOTIFICATION_SERVICE);

        //All notifications should go through NotificationChannel on Android 26 & above
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel channel = new NotificationChannel(CHANNEL_ID,

        notificationManager.notify(NOTIFICATION_ID, notification);


Hope it will help :)

addEventListener, "change" and option selection

The problem is that you used the select option, this is where you went wrong. Select signifies that a textbox or textArea has a focus. What you need to do is use change. "Fires when a new choice is made in a select element", also used like blur when moving away from a textbox or textArea.

function start(){
      document.getElementById("activitySelector").addEventListener("change", addActivityItem, false);

function addActivityItem(){
      //option is selected

window.addEventListener("load", start, false);

How to open CSV file in R when R says "no such file or directory"?

I had the same problem and when I checked the properties of the file on file explorer, it shows me the next message:

"Security: This file came from another computer and might be blocked to help protect this computer"

You click on the "Unblock" button and... you can access to the file from R without any problem, just using read.csv() function and from the directory specified as your working directory, even if is not the same as the file’s directory you are accessing to.

Creating a fixed sidebar alongside a centered Bootstrap 3 grid

As drew_w said, you can find a good example here.


<div id="wrapper">
    <div id="sidebar-wrapper">
        <ul class="sidebar-nav">
            <li class="sidebar-brand"><a href="#">Home</a></li>
            <li><a href="#">Another link</a></li>
            <li><a href="#">Next link</a></li>
            <li><a href="#">Last link</a></li>
    <div id="page-content-wrapper">
        <div class="page-content">
            <div class="container">
                <div class="row">
                    <div class="col-md-12">
                        <!-- content of page -->


#wrapper {
  padding-left: 250px;
  transition: all 0.4s ease 0s;

#sidebar-wrapper {
  margin-left: -250px;
  left: 250px;
  width: 250px;
  background: #CCC;
  position: fixed;
  height: 100%;
  overflow-y: auto;
  z-index: 1000;
  transition: all 0.4s ease 0s;

#page-content-wrapper {
  width: 100%;

.sidebar-nav {
  position: absolute;
  top: 0;
  width: 250px;
  list-style: none;
  margin: 0;
  padding: 0;

@media (max-width:767px) {

    #wrapper {
      padding-left: 0;

    #sidebar-wrapper {
      left: 0;
    } {
      position: relative;
      left: 250px;
    } #sidebar-wrapper {
      left: 250px;
      width: 250px;
      transition: all 0.4s ease 0s;



Java equivalent to C# extension methods

It looks like there is some small chance that Defender Methods (i.e. default methods) might make it into Java 8. However, as far as I understand them, they only allow the author of an interface to retroactively extend it, not arbitrary users.

Defender Methods + Interface Injection would then be able to fully implement C#-style extension methods, but AFAICS, Interface Injection isn't even on the Java 8 road-map yet.

How do I fix MSB3073 error in my post-build event?

Playing around with different project properties, I found that the project build order was the problem. The project that generated the files I wanted to copy was built second, but the project that was running the batch file as a post-build event was built first, so I simply attached the build event to the second project instead, and it works just fine. Thanks for your help, everyone, though.

python and sys.argv

I would do it this way:

import sys

def main(argv):
    if len(argv) < 2:
        sys.stderr.write("Usage: %s <database>" % (argv[0],))
        return 1

    if not os.path.exists(argv[1]):
        sys.stderr.write("ERROR: Database %r was not found!" % (argv[1],))
        return 1

if __name__ == "__main__":

This allows main() to be imported into other modules if desired, and simplifies debugging because you can choose what argv should be.

What does operator "dot" (.) mean?

There is a whole page in the MATLAB documentation dedicated to this topic: Array vs. Matrix Operations. The gist of it is below:

MATLAB® has two different types of arithmetic operations: array operations and matrix operations. You can use these arithmetic operations to perform numeric computations, for example, adding two numbers, raising the elements of an array to a given power, or multiplying two matrices.

Matrix operations follow the rules of linear algebra. By contrast, array operations execute element by element operations and support multidimensional arrays. The period character (.) distinguishes the array operations from the matrix operations. However, since the matrix and array operations are the same for addition and subtraction, the character pairs .+ and .- are unnecessary.

Color Tint UIButton Image

Swift 4 with customType:

let button = UIButton(frame: aRectHere)
    let buttonImage = UIImage(named: "imageName")
    button.setImage(buttonImage?.withRenderingMode(.alwaysTemplate), for: .normal)
    button.tintColor = .white

How can I make my custom objects Parcelable?

1. Import Android Parcelable code generator

enter image description here

2. Create a class

public class Sample {
    int id;
    String name;

3. Generate > Parcelable from menu

enter image description here enter image description here


C: What is the difference between ++i and i++?


++i and i++ works same if you are not writing them in a function. If you use something like function(i++) or function(++i) you can see the difference.

function(++i) says first increment i by 1, after that put this i into the function with new value.

function(i++) says put first i into the function after that increment i by 1.

int i=4;
printf("%d\n",pow(++i,2));//it prints 25 and i is 5 now
printf("%d",pow(i++,2));//it prints 16 i is 5 now

How do I tell Spring Boot which main class to use for the executable jar?

Add your start class in your pom:

    <!-- The main class to start by executing java -jar -->



Setting the zoom level for a MKMapView

I hope following code fragment would help you.

- (void)handleZoomOutAction:(id)sender {
    MKCoordinateRegion newRegion=MKCoordinateRegionMake(,MKCoordinateSpanMake(mapView.region.s       pan.latitudeDelta/0.5, mapView.region.span.longitudeDelta/0.5));
    [mapView setRegion:newRegion];

- (void)handleZoomInAction:(id)sender {
    MKCoordinateRegion newRegion=MKCoordinateRegionMake(,MKCoordinateSpanMake(mapView.region.span.latitudeDelta*0.5, mapView.region.span.longitudeDelta*0.5));
    [mapView setRegion:newRegion];

You can choose any value in stead of 0.5 to reduce or increase zoom level. I have used these methods on click of two buttons.

Post parameter is always null

I am pretty late to this but was having similar issues and after a day of going through a lot of the answers here and getting background I have found the easiest/lightweight solution to pass back one or more parameters to a Web API 2 Action is as follows:

This assumes that you know how to setup a Web API controller/action with correct routing, if not refer to:

First the Controller Action, this solution also requires the Newtonsoft.Json library.

public string PostProcessData([FromBody]string parameters) {
    if (!String.IsNullOrEmpty(parameters)) {
        JObject json = JObject.Parse(parameters);

        // Code logic below
        // Can access params via json["paramName"].ToString();
    return "";

Client Side using jQuery

var dataToSend = JSON.stringify({ param1: "value1", param2: "value2"...});
$.post('/Web_API_URI', { '': dataToSend }).done(function (data) {
     console.debug(data); // returned data from Web API

The key issue I found was making sure you only send a single overall parameter back to the Web API and make sure it has no name just the value { '': dataToSend }otherwise your value will be null on the server side.

With this you can send one or many parameters to the Web API in a JSON structure and you don't need to declare any extra objects server side to handle complex data. The JObject also allows you to dynamically iterate over all parameters passed in allowing easier scalability should your parameters change over time. Hopefully that helps someone out that was struggling like me.

"Retrieving the COM class factory for component.... error: 80070005 Access is denied." (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))

solution that worked for me is to change user under which Application Pool is started (ApplicationPoolIdentity obviously has not enough rights to access COM object).

Good luck!

Which is faster: Stack allocation or Heap allocation

I don't think stack allocation and heap allocation are generally interchangable. I also hope that the performance of both of them is sufficient for general use.

I'd strongly recommend for small items, whichever one is more suitable to the scope of the allocation. For large items, the heap is probably necessary.

On 32-bit operating systems that have multiple threads, stack is often rather limited (albeit typically to at least a few mb), because the address space needs to be carved up and sooner or later one thread stack will run into another. On single threaded systems (Linux glibc single threaded anyway) the limitation is much less because the stack can just grow and grow.

On 64-bit operating systems there is enough address space to make thread stacks quite large.

Fade Effect on Link Hover?

You can do this with JQueryUI:

    color: '#ff0000'
  }, 1000);
    color: '#000000'
  }, 1000);

How to get a password from a shell script without echoing

For anyone needing to prompt for a password, you may be interested in using This is a script I wrote for similar purposes of capturing a secret at runtime and then encrypting it for subsequent occasions. Subsequent runs do not prompt for the password as it will just use the encrypted value from disk.

It stores the encrypted passwords in a hidden folder under the user's home directory or in a custom folder that you can define through the environment variable ENCPASS_HOME_DIR. It is designed to be POSIX compliant and has an MIT License, so it can be used even in corporate enterprise environments. My company, Plyint LLC, maintains the script and occasionally releases updates. Pull requests are also welcome, if you find an issue. :)

To use it in your scripts simply source in your script and call the get_secret function. I'm including a copy of the script below for easy visibility.

# Copyright (c) 2020 Plyint, LLC <[email protected]>. All Rights Reserved.
# This file is licensed under the MIT License (MIT). 
# Please see LICENSE.txt for more information.
# This script allows a user to encrypt a password (or any other secret) at 
# runtime and then use it, decrypted, within a script.  This prevents shoulder 
# surfing passwords and avoids storing the password in plain text, which could 
# inadvertently be sent to or discovered by an individual at a later date.
# This script generates an AES 256 bit symmetric key for each script (or user-
# defined bucket) that stores secrets.  This key will then be used to encrypt 
# all secrets for that script or bucket. sets up a directory 
# (.encpass) under the user's home directory where keys and secrets will be 
# stored.
# For further details, see or run "./encpass ?" from the command line.

encpass_checks() {
    if [ -n "$ENCPASS_CHECKS" ]; then

    if [ ! -x "$(command -v openssl)" ]; then
        echo "Error: OpenSSL is not installed or not accessible in the current path." \
            "Please install it and try again." >&2
        exit 1

    if [ -z "$ENCPASS_HOME_DIR" ]; then
        ENCPASS_HOME_DIR=$(encpass_get_abs_filename ~)/.encpass

    if [ ! -d "$ENCPASS_HOME_DIR" ]; then
        mkdir -m 700 "$ENCPASS_HOME_DIR"
        mkdir -m 700 "$ENCPASS_HOME_DIR/keys"
        mkdir -m 700 "$ENCPASS_HOME_DIR/secrets"

    if [ "$(basename "$0")" != "" ]; then
        encpass_include_init "$1" "$2"


# Initializations performed when the script is included by another script
encpass_include_init() {
    if [ -n "$1" ] && [ -n "$2" ]; then
    elif [ -n "$1" ]; then
        ENCPASS_BUCKET=$(basename "$0")
        ENCPASS_BUCKET=$(basename "$0")

encpass_generate_private_key() {

    if [ ! -d "$ENCPASS_KEY_DIR" ]; then
        mkdir -m 700 "$ENCPASS_KEY_DIR"

    if [ ! -f "$ENCPASS_KEY_DIR/private.key" ]; then
        (umask 0377 && printf "%s" "$(openssl rand -hex 32)" >"$ENCPASS_KEY_DIR/private.key")

encpass_get_private_key_abs_name() {

    if [ "$1" != "nogenerate" ]; then 
        if [ ! -f "$ENCPASS_PRIVATE_KEY_ABS_NAME" ]; then

encpass_get_secret_abs_name() {

    if [ "$3" != "nocreate" ]; then 
        if [ ! -f "$ENCPASS_SECRET_ABS_NAME" ]; then
            set_secret "$1" "$2"

get_secret() {
    encpass_checks "$1" "$2"
    encpass_get_secret_abs_name "$1" "$2"

set_secret() {
    encpass_checks "$1" "$2"

    if [ "$3" != "reuse" ] || { [ -z "$ENCPASS_SECRET_INPUT" ] && [ -z "$ENCPASS_CSECRET_INPUT" ]; }; then
        echo "Enter $ENCPASS_SECRET_NAME:" >&2
        stty -echo
        read -r ENCPASS_SECRET_INPUT
        stty echo
        echo "Confirm $ENCPASS_SECRET_NAME:" >&2
        stty -echo
        stty echo


        if [ ! -d "$ENCPASS_SECRET_DIR" ]; then
            mkdir -m 700 "$ENCPASS_SECRET_DIR"

        printf "%s" "$(openssl rand -hex 16)" >"$ENCPASS_SECRET_DIR/$ENCPASS_SECRET_NAME.enc"


        echo "$ENCPASS_SECRET_INPUT" | openssl enc -aes-256-cbc -e -a -iv \
            "$ENCPASS_OPENSSL_IV" -K \
            "$(cat "$ENCPASS_HOME_DIR/keys/$ENCPASS_BUCKET/private.key")" 1>> \
        echo "Error: secrets do not match.  Please try again." >&2
        exit 1

encpass_get_abs_filename() {
    # $1 : relative filename
    parentdir="$(dirname "${filename}")"

    if [ -d "${filename}" ]; then
        cd "${filename}" && pwd
    elif [ -d "${parentdir}" ]; then
        echo "$(cd "${parentdir}" && pwd)/$(basename "${filename}")"

encpass_decrypt_secret() {
    if [ -f "$ENCPASS_PRIVATE_KEY_ABS_NAME" ]; then
        ENCPASS_DECRYPT_RESULT="$(dd if="$ENCPASS_SECRET_ABS_NAME" ibs=1 skip=32 2> /dev/null | openssl enc -aes-256-cbc \
            -d -a -iv "$(head -c 32 "$ENCPASS_SECRET_ABS_NAME")" -K "$(cat "$ENCPASS_PRIVATE_KEY_ABS_NAME")" 2> /dev/null)"
        if [ ! -z "$ENCPASS_DECRYPT_RESULT" ]; then
            echo "$ENCPASS_DECRYPT_RESULT"
            # If a failed unlock command occurred and the user tries to show the secret
            # Present either locked or decrypt command
            if [ -f "$ENCPASS_HOME_DIR/keys/$ENCPASS_BUCKET/private.lock" ]; then 
            echo "**Locked**"
                # The locked file wasn't present as expected.  Let's display a failure
            echo "Error: Failed to decrypt"
    elif [ -f "$ENCPASS_HOME_DIR/keys/$ENCPASS_BUCKET/private.lock" ]; then
        echo "**Locked**"
        echo "Error: Unable to decrypt. The key file \"$ENCPASS_PRIVATE_KEY_ABS_NAME\" is not present."

# -------------------------------
# If you don't need to manage the secrets for the scripts
# with you can delete all code below this point
# in order to significantly reduce the size of
# This is useful if you want to bundle with
# your existing scripts and just need the retrieval
# functions.

encpass_show_secret() {

    encpass_get_private_key_abs_name "nogenerate"

    if [ ! -z "$2" ]; then
        encpass_get_secret_abs_name "$1" "$2" "nocreate"
        if [ -z "$ENCPASS_SECRET_ABS_NAME" ]; then
            echo "No secret named $2 found for bucket $1."
            exit 1

        ENCPASS_FILE_LIST=$(ls -1 "$ENCPASS_HOME_DIR"/secrets/"$1")
        for ENCPASS_F in $ENCPASS_FILE_LIST; do
            ENCPASS_SECRET_NAME=$(basename "$ENCPASS_F" .enc)

            encpass_get_secret_abs_name "$1" "$ENCPASS_SECRET_NAME" "nocreate"
            if [ -z "$ENCPASS_SECRET_ABS_NAME" ]; then
                echo "No secret named $ENCPASS_SECRET_NAME found for bucket $1."
                exit 1

            echo "$ENCPASS_SECRET_NAME = $(encpass_decrypt_secret)"

encpass_getche() {
        old=$(stty -g)
        stty raw min 1 time 0
        printf '%s' "$(dd bs=1 count=1 2>/dev/null)"
        stty "$old"

encpass_remove() {
    if [ ! -n "$ENCPASS_FORCE_REMOVE" ]; then
        if [ ! -z "$ENCPASS_SECRET" ]; then
            printf "Are you sure you want to remove the secret \"%s\" from bucket \"%s\"? [y/N]" "$ENCPASS_SECRET" "$ENCPASS_BUCKET"
            printf "Are you sure you want to remove the bucket \"%s?\" [y/N]" "$ENCPASS_BUCKET"

        printf "\n"
        if [ "$ENCPASS_CONFIRM" != "Y" ] && [ "$ENCPASS_CONFIRM" != "y" ]; then
            exit 0

    if [ ! -z "$ENCPASS_SECRET" ]; then
        rm -f "$1"
        printf "Secret \"%s\" removed from bucket \"%s\".\n" "$ENCPASS_SECRET" "$ENCPASS_BUCKET"
        rm -Rf "$ENCPASS_HOME_DIR/secrets/$ENCPASS_BUCKET"
        printf "Bucket \"%s\" removed.\n" "$ENCPASS_BUCKET"

encpass_save_err() {
    if read -r x; then
        { printf "%s\n" "$x"; cat; } > "$1"
    elif [ "$x" != "" ]; then
        printf "%s" "$x" > "$1"

encpass_help() {
less << EOF
NAME: - Use encrypted passwords in shell scripts

    A lightweight solution for using encrypted passwords in shell scripts 
    using OpenSSL. It allows a user to encrypt a password (or any other secret)
    at runtime and then use it, decrypted, within a script. This prevents
    shoulder surfing passwords and avoids storing the password in plain text, 
    within a script, which could inadvertently be sent to or discovered by an 
    individual at a later date.

    This script generates an AES 256 bit symmetric key for each script 
    (or user-defined bucket) that stores secrets. This key will then be used 
    to encrypt all secrets for that script or bucket.

    Subsequent calls to retrieve a secret will not prompt for a secret to be 
    entered as the file with the encrypted value already exists.

    Note: By default, sets up a directory (.encpass) under the 
    user's home directory where keys and secrets will be stored.  This directory
    can be overridden by setting the environment variable ENCPASS_HOME_DIR to a
    directory of your choice.

    ~/.encpass (or the directory specified by ENCPASS_HOME_DIR) will contain 
    the following subdirectories:
      - keys (Holds the private key for each script/bucket)
      - secrets (Holds the secrets stored for each script/bucket)

    To use the script in an existing shell script, source the script 
    and then call the get_secret function.



    When no arguments are passed to the get_secret function,
    then the bucket name is set to the name of the script and
    the secret name is set to "password".

    There are 2 other ways to call get_secret:

      Specify the secret name:
      Ex: \$(get_secret user)
        - bucket name = <script name>
        - secret name = "user"

      Specify both the secret name and bucket name:
      Ex: \$(get_secret personal user)
        - bucket name = "personal"
        - secret name = "user" also provides a command line interface to manage the secrets.
    To invoke a command, pass it as an argument to from the shell.

        $ [COMMAND]

    See the COMMANDS section below for a list of available commands.  Wildcard
    handling is implemented for secret and bucket names.  This enables
    performing operations like adding/removing a secret to/from multiple buckets
        at once.

    add [-f] <bucket> <secret>
        Add a secret to the specified bucket.  The bucket will be created
        if it does not already exist. If a secret with the same name already
        exists for the specified bucket, then the user will be prompted to
        confirm overwriting the value.  If the -f option is passed, then the
        add operation will perform a forceful overwrite of the value. (i.e. no

    list|ls [<bucket>]
        Display the names of the secrets held in the bucket.  If no bucket
        is specified, then the names of all existing buckets will be

        Locks all keys used by using a password.  The user
        will be prompted to enter a password and confirm it.  A user
        should take care to securely store the password.  If the password
        is lost then keys can not be unlocked.  When keys are locked,
        secrets can not be retrieved. (e.g. the output of the values
        in the "show" command will be encrypted/garbage)

    remove|rm [-f] <bucket> [<secret>]
        Remove a secret from the specified bucket.  If only a bucket is
        specified then the entire bucket (i.e. all secrets and keys) will
        be removed.  By default the user is asked to confirm the removal of
        the secret or the bucket.  If the -f option is passed then a 
        forceful removal will be performed.  (i.e. no prompt)

    show [<bucket>] [<secret>]
        Show the unencrypted value of the secret from the specified bucket.
        If no secret is specified then all secrets for the bucket are displayed.

    update <bucket> <secret>
        Updates a secret in the specified bucket.  This command is similar
        to using an "add -f" command, but it has a safety check to only 
        proceed if the specified secret exists.  If the secret, does not
        already exist, then an error will be reported. There is no forceable
        update implemented.  Use "add -f" for any required forceable update

        Unlocks all the keys for  The user will be prompted to 
        enter the password and confirm it.

        Prints out the current value of the ENCPASS_HOME_DIR environment variable.

        Display this help message.

# Subcommands for cli support
case "$1" in
    add )
        while getopts ":f" ENCPASS_OPTS; do
            case "$ENCPASS_OPTS" in
                f ) ENCPASS_FORCE_ADD=1;;


        if [ -n "$ENCPASS_FORCE_ADD" ]; then
            shift $((OPTIND-1))

        if [ ! -z "$1" ] && [ ! -z "$2" ]; then
            # Allow globbing
            # shellcheck disable=SC2027,SC2086
            ENCPASS_ADD_LIST="$(ls -1d "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"
            if [ -z "$ENCPASS_ADD_LIST" ]; then

            for ENCPASS_ADD_F in $ENCPASS_ADD_LIST; do
                ENCPASS_ADD_DIR="$(basename "$ENCPASS_ADD_F")"
                if [ ! -n "$ENCPASS_FORCE_ADD" ] && [ -f "$ENCPASS_ADD_F/$2.enc" ]; then
                    echo "Warning: A secret with the name \"$2\" already exists for bucket $ENCPASS_BUCKET."
                    echo "Would you like to overwrite the value? [y/N]"

                    if [ "$ENCPASS_CONFIRM" != "Y" ] && [ "$ENCPASS_CONFIRM" != "y" ]; then

                echo "Adding secret \"$ENCPASS_SECRET_NAME\" to bucket \"$ENCPASS_BUCKET\"..."
                set_secret "$ENCPASS_BUCKET" "$ENCPASS_SECRET_NAME" "reuse"
            echo "Error: A bucket name and secret name must be provided when adding a secret."
            exit 1
    update )

        if [ ! -z "$1" ] && [ ! -z "$2" ]; then

            # Allow globbing
            # shellcheck disable=SC2027,SC2086
            ENCPASS_UPDATE_LIST="$(ls -1d "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"

                # Allow globbing
                # shellcheck disable=SC2027,SC2086
                if [ -f "$ENCPASS_UPDATE_F/"$2".enc" ]; then
                        ENCPASS_UPDATE_DIR="$(basename "$ENCPASS_UPDATE_F")"
                        echo "Updating secret \"$ENCPASS_SECRET_NAME\" to bucket \"$ENCPASS_BUCKET\"..."
                        set_secret "$ENCPASS_BUCKET" "$ENCPASS_SECRET_NAME" "reuse"
                    echo "Error: A secret with the name \"$2\" does not exist for bucket $1."
                    exit 1
            echo "Error: A bucket name and secret name must be provided when updating a secret."
            exit 1
    rm|remove )

        while getopts ":f" ENCPASS_OPTS; do
            case "$ENCPASS_OPTS" in
                f ) ENCPASS_FORCE_REMOVE=1;;

        if [ -n "$ENCPASS_FORCE_REMOVE" ]; then
            shift $((OPTIND-1))

        if [ -z "$1" ]; then 
            echo "Error: A bucket must be specified for removal."

        # Allow globbing
        # shellcheck disable=SC2027,SC2086
        ENCPASS_REMOVE_BKT_LIST="$(ls -1d "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"
        if [ ! -z "$ENCPASS_REMOVE_BKT_LIST" ]; then

                ENCPASS_BUCKET="$(basename "$ENCPASS_REMOVE_B")"
                if [ ! -z "$2" ]; then
                    # Removing secrets for a specified bucket
                    # Allow globbing
                    # shellcheck disable=SC2027,SC2086
                    ENCPASS_REMOVE_LIST="$(ls -1p "$ENCPASS_REMOVE_B/"$2".enc" 2>/dev/null)"

                    if [ -z "$ENCPASS_REMOVE_LIST" ]; then
                        echo "Error: No secrets found for $2 in bucket $ENCPASS_BUCKET."
                        exit 1

                    for ENCPASS_REMOVE_F in $ENCPASS_REMOVE_LIST; do
                        encpass_remove "$ENCPASS_REMOVE_F"
                    # Removing a specified bucket

            echo "Error: The bucket named $1 does not exist."
            exit 1
    show )
        if [ -z "$1" ]; then

        if [ ! -z "$2" ]; then
            # Allow globbing
            # shellcheck disable=SC2027,SC2086
            if [ -f "$(encpass_get_abs_filename "$ENCPASS_HOME_DIR/secrets/$ENCPASS_SHOW_DIR/"$2".enc")" ]; then
                encpass_show_secret "$ENCPASS_SHOW_DIR" "$2"
            # Allow globbing
            # shellcheck disable=SC2027,SC2086
            ENCPASS_SHOW_LIST="$(ls -1d "$ENCPASS_HOME_DIR/secrets/"$ENCPASS_SHOW_DIR"" 2>/dev/null)"

            if [ -z "$ENCPASS_SHOW_LIST" ]; then
                if [ "$ENCPASS_SHOW_DIR" = "*" ]; then
                    echo "Error: No buckets exist."
                    echo "Error: Bucket $1 does not exist."
                exit 1

            for ENCPASS_SHOW_F in $ENCPASS_SHOW_LIST; do
                ENCPASS_SHOW_DIR="$(basename "$ENCPASS_SHOW_F")"
                echo "$ENCPASS_SHOW_DIR:"
                encpass_show_secret "$ENCPASS_SHOW_DIR"
                echo " "
    ls|list )
        if [ ! -z "$1" ]; then
            # Allow globbing
            # shellcheck disable=SC2027,SC2086
            ENCPASS_FILE_LIST="$(ls -1p "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"

            if [ -z "$ENCPASS_FILE_LIST" ]; then
                # Allow globbing
                # shellcheck disable=SC2027,SC2086
                ENCPASS_DIR_EXISTS="$(ls -d "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"
                if [ ! -z "$ENCPASS_DIR_EXISTS" ]; then
                    echo "Bucket $1 is empty."
                    echo "Error: Bucket $1 does not exist."
                exit 1

            for ENCPASS_F in $ENCPASS_FILE_LIST; do
                if [ -d "${ENCPASS_F%:}" ]; then
                    printf "$ENCPASS_NL%s\n" "$(basename "$ENCPASS_F")"
                    printf "%s\n" "$(basename "$ENCPASS_F" .enc)"
            # Allow globbing
            # shellcheck disable=SC2027,SC2086
            ENCPASS_BUCKET_LIST="$(ls -1p "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"
            for ENCPASS_C in $ENCPASS_BUCKET_LIST; do
                if [ -d "${ENCPASS_C%:}" ]; then
                    printf "\n%s" "\n$(basename "$ENCPASS_C")"
                    basename "$ENCPASS_C" .enc
    lock )

        echo "************************!!!WARNING!!!*************************" >&2
        echo "* You are about to lock your keys with a password.           *" >&2
        echo "* You will not be able to use your secrets again until you   *" >&2
        echo "* unlock the keys with the same password. It is important    *" >&2
        echo "* that you securely store the password, so you can recall it *" >&2
        echo "* in the future.  If you forget your password you will no    *" >&2
        echo "* longer be able to access your secrets.                     *" >&2
        echo "************************!!!WARNING!!!*************************" >&2

        printf "\n%s\n" "About to lock keys held in directory $ENCPASS_HOME_DIR/keys/"

        printf "\nEnter Password to lock keys:" >&2
        stty -echo
        read -r ENCPASS_KEY_PASS
        printf "\nConfirm Password:" >&2
        read -r ENCPASS_CKEY_PASS
        printf "\n"
        stty echo

        if [ -z "$ENCPASS_KEY_PASS" ]; then
            echo "Error: You must supply a password value."
            exit 1

        if [ "$ENCPASS_KEY_PASS" = "$ENCPASS_CKEY_PASS" ]; then
            ENCPASS_KEYS_LIST="$(ls -1d "$ENCPASS_HOME_DIR/keys/"*"/" 2>/dev/null)"
            for ENCPASS_KEY_F in $ENCPASS_KEYS_LIST; do

                if [ -d "${ENCPASS_KEY_F%:}" ]; then
                    ENCPASS_KEY_NAME="$(basename "$ENCPASS_KEY_F")"
                    if [ -f "$ENCPASS_KEY_F/private.key" ]; then
                        ENCPASS_KEY_VALUE="$(cat "$ENCPASS_KEY_F/private.key")"
                        if [ ! -f "$ENCPASS_KEY_F/private.lock" ]; then
                        echo "Locking key $ENCPASS_KEY_NAME..."
                          echo "Error: The key $ENCPASS_KEY_NAME appears to have been previously locked."
                            echo "       The current key file may hold a bad value. Exiting to avoid encrypting"
                            echo "       a bad value and overwriting the lock file."
                            exit 1
                        echo "Error: Private key file ${ENCPASS_KEY_F}private.key missing for bucket $ENCPASS_KEY_NAME."
                        exit 1
                    if [ ! -z "$ENCPASS_KEY_VALUE" ]; then
                        openssl enc -aes-256-cbc -pbkdf2 -iter 10000 -salt -in "$ENCPASS_KEY_F/private.key" -out "$ENCPASS_KEY_F/private.lock" -k "$ENCPASS_KEY_PASS"
                        if [ -f "$ENCPASS_KEY_F/private.key" ] && [ -f "$ENCPASS_KEY_F/private.lock" ]; then
                            # Both the key and lock file exist.  We can remove the key file now
                            rm -f "$ENCPASS_KEY_F/private.key"
                            echo "Locked key $ENCPASS_KEY_NAME."
                            ENCPASS_NUM_KEYS_LOCKED=$(( ENCPASS_NUM_KEYS_LOCKED + 1 ))
                            echo "Error: The key fle and/or lock file were not found as expected for key $ENCPASS_KEY_NAME."
                        echo "Error: No key value found for the $ENCPASS_KEY_NAME key."
                        exit 1
            echo "Locked $ENCPASS_NUM_KEYS_LOCKED keys."
            echo "Error: Passwords do not match."
    unlock )

        printf "%s\n" "About to unlock keys held in the $ENCPASS_HOME_DIR/keys/ directory."

        printf "\nEnter Password to unlock keys: " >&2
        stty -echo
        read -r ENCPASS_KEY_PASS
        printf "\n"
        stty echo

        if [ ! -z "$ENCPASS_KEY_PASS" ]; then
            ENCPASS_KEYS_LIST="$(ls -1d "$ENCPASS_HOME_DIR/keys/"*"/" 2>/dev/null)"
            for ENCPASS_KEY_F in $ENCPASS_KEYS_LIST; do

                if [ -d "${ENCPASS_KEY_F%:}" ]; then
                    ENCPASS_KEY_NAME="$(basename "$ENCPASS_KEY_F")"
                    echo "Unlocking key $ENCPASS_KEY_NAME..."
                    if [ -f "$ENCPASS_KEY_F/private.key" ] && [ ! -f "$ENCPASS_KEY_F/private.lock" ]; then
                        echo "Error: Key $ENCPASS_KEY_NAME appears to be unlocked already."
                        exit 1

                    if [ -f "$ENCPASS_KEY_F/private.lock" ]; then
                        # Remove the failed file in case previous decryption attempts were unsuccessful
                        rm -f "$ENCPASS_KEY_F/failed" 2>/dev/null

                        # Decrypt key. Log any failure to the "failed" file.
                        openssl enc -aes-256-cbc -d -pbkdf2 -iter 10000 -salt \
                            -in "$ENCPASS_KEY_F/private.lock" -out "$ENCPASS_KEY_F/private.key" \
                            -k "$ENCPASS_KEY_PASS" 2>&1 | encpass_save_err "$ENCPASS_KEY_F/failed"

                        if [ ! -f "$ENCPASS_KEY_F/failed" ]; then
                            # No failure has occurred.
                          if [ -f "$ENCPASS_KEY_F/private.key" ] && [ -f "$ENCPASS_KEY_F/private.lock" ]; then
                              # Both the key and lock file exist.  We can remove the lock file now.
                              rm -f "$ENCPASS_KEY_F/private.lock"
                              echo "Unlocked key $ENCPASS_KEY_NAME."
                              ENCPASS_NUM_KEYS_UNLOCKED=$(( ENCPASS_NUM_KEYS_UNLOCKED + 1 ))
                              echo "Error: The key file and/or lock file were not found as expected for key $ENCPASS_KEY_NAME."
                          printf "Error: Failed to unlock key %s.\n" "$ENCPASS_KEY_NAME"
                            printf "       Please view %sfailed for details.\n" "$ENCPASS_KEY_F"
                        echo "Error: No lock file found for the $ENCPASS_KEY_NAME key."
            echo "Unlocked $ENCPASS_NUM_KEYS_UNLOCKED keys."
            echo "No password entered."
    dir )
    help|--help|usage|--usage|\? )
    * )
        if [ ! -z "$1" ]; then
            echo "Command not recognized. See \" help\" for a list commands."
            exit 1

Count number of cells with any value (string or number) in a column in Google Docs Spreadsheet

An additional trick beside using =COUNTIF(...) and =COUNTA(...) is:


That will count all the empty cells.

This is useful for:

  • empty cells that doesn't contain data
  • formula that return blank or null
  • survey with missing answer fields which can be used for diff criterias

How to fix IndexError: invalid index to scalar variable

Basically, 1 is not a valid index of y. If the visitor is comming from his own code he should check if his y contains the index which he tries to access (in this case the index is 1).

getOutputStream() has already been called for this response

JSP is s presentation framework, and is generally not supposed to contain any program logic in it. As skaffman suggested, use pure servlets, or any MVC web framework in order to achieve what you want.

How to make Excel VBA variables available to multiple macros?

You may consider declaring the variables with moudule level scope. Module-level variable is available to all of the procedures in that module, but it is not available to procedures in other modules

For details on Scope of variables refer this link

Please copy the below code into any module, save the workbook and then run the code.

Here is what code does

  • The sample subroutine sets the folder path & later the file path. Kindly set them accordingly before you run the code.

  • I have added a function IsWorkBookOpen to check if workbook is already then set the workbook variable the workbook name else open the workbook which will be assigned to workbook variable accordingly.

Dim wbA As Workbook
Dim wbB As Workbook

Sub MySubRoutine()
    Dim folderPath As String, fileNm1 As String, fileNm2 As String, filePath1 As String, filePath2 As String

    folderPath = ThisWorkbook.Path & "\"
    fileNm1 = "file1.xlsx"
    fileNm2 = "file2.xlsx"

    filePath1 = folderPath & fileNm1
    filePath2 = folderPath & fileNm2

    If IsWorkBookOpen(filePath1) Then
        Set wbA = Workbooks(fileNm1)
        Set wbA = Workbooks.Open(filePath1)
    End If

    If IsWorkBookOpen(filePath2) Then
        Set wbB = Workbooks.Open(fileNm2)
        Set wbB = Workbooks.Open(filePath2)
    End If

    ' your code here
End Sub

Function IsWorkBookOpen(FileName As String)
    Dim ff As Long, ErrNo As Long

    On Error Resume Next
    ff = FreeFile()
    Open FileName For Input Lock Read As #ff
    Close ff
    ErrNo = Err
    On Error GoTo 0

    Select Case ErrNo
    Case 0: IsWorkBookOpen = False
    Case 70: IsWorkBookOpen = True
    Case Else: Error ErrNo
    End Select
End Function

Using Prompt to select the file use below code.

Dim wbA As Workbook
Dim wbB As Workbook

Sub MySubRoutine()
    Dim folderPath As String, fileNm1 As String, fileNm2 As String, filePath1 As String, filePath2 As String

    Dim filePath As String
    cmdBrowse_Click filePath, 1

    filePath1 = filePath

    'reset the variable
    filePath = vbNullString

    cmdBrowse_Click filePath, 2
    filePath2 = filePath

   fileNm1 = GetFileName(filePath1, "\")
   fileNm2 = GetFileName(filePath2, "\")

    If IsWorkBookOpen(filePath1) Then
        Set wbA = Workbooks(fileNm1)
        Set wbA = Workbooks.Open(filePath1)
    End If

    If IsWorkBookOpen(filePath2) Then
        Set wbB = Workbooks.Open(fileNm2)
        Set wbB = Workbooks.Open(filePath2)
    End If

    ' your code here
End Sub

Function IsWorkBookOpen(FileName As String)
    Dim ff As Long, ErrNo As Long

    On Error Resume Next
    ff = FreeFile()
    Open FileName For Input Lock Read As #ff
    Close ff
    ErrNo = Err
    On Error GoTo 0

    Select Case ErrNo
    Case 0: IsWorkBookOpen = False
    Case 70: IsWorkBookOpen = True
    Case Else: Error ErrNo
    End Select
End Function

Private Sub cmdBrowse_Click(ByRef filePath As String, num As Integer)

    Dim fd As FileDialog
    Set fd = Application.FileDialog(msoFileDialogFilePicker)
    fd.AllowMultiSelect = False
    fd.Title = "Select workbook " & num
    fd.InitialView = msoFileDialogViewSmallIcons

    Dim FileChosen As Integer

    FileChosen = fd.Show

    fd.Filters.Add "Excel macros", "*.xlsx"

    fd.FilterIndex = 1

    If FileChosen <> -1 Then
        MsgBox "You chose cancel"
        filePath = ""
        filePath = fd.SelectedItems(1)
    End If

End Sub

Function GetFileName(fullName As String, pathSeparator As String) As String

    Dim i As Integer
    Dim iFNLenght As Integer
    iFNLenght = Len(fullName)

    For i = iFNLenght To 1 Step -1
        If Mid(fullName, i, 1) = pathSeparator Then Exit For

    GetFileName = Right(fullName, iFNLenght - i)

End Function

Int to Decimal Conversion - Insert decimal point at specified location

int i = 7122960;
decimal d = (decimal)i / 100;

How can I delete a file from a Git repository?

Use git rm.

If you want to remove the file from the Git repository and the filesystem, use:

git rm file1.txt
git commit -m "remove file1.txt"

But if you want to remove the file only from the Git repository and not remove it from the filesystem, use:

git rm --cached file1.txt
git commit -m "remove file1.txt"

And to push changes to remote repo

git push origin branch_name

How to get a path to the desktop for current user in C#?

// Environment.GetFolderPath
Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData); // Current User's Application Data
Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData); // All User's Application Data
Environment.GetFolderPath(Environment.SpecialFolder.CommonProgramFiles); // Program Files
Environment.GetFolderPath(Environment.SpecialFolder.Cookies); // Internet Cookie
Environment.GetFolderPath(Environment.SpecialFolder.Desktop); // Logical Desktop
Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory); // Physical Desktop
Environment.GetFolderPath(Environment.SpecialFolder.Favorites); // Favorites
Environment.GetFolderPath(Environment.SpecialFolder.History); // Internet History
Environment.GetFolderPath(Environment.SpecialFolder.InternetCache); // Internet Cache
Environment.GetFolderPath(Environment.SpecialFolder.MyComputer); // "My Computer" Folder
Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments); // "My Documents" Folder
Environment.GetFolderPath(Environment.SpecialFolder.MyMusic); // "My Music" Folder
Environment.GetFolderPath(Environment.SpecialFolder.MyPictures); // "My Pictures" Folder
Environment.GetFolderPath(Environment.SpecialFolder.Personal); // "My Document" Folder
Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles); // Program files Folder
Environment.GetFolderPath(Environment.SpecialFolder.Programs); // Programs Folder
Environment.GetFolderPath(Environment.SpecialFolder.Recent); // Recent Folder
Environment.GetFolderPath(Environment.SpecialFolder.SendTo); // "Sent to" Folder
Environment.GetFolderPath(Environment.SpecialFolder.StartMenu); // Start Menu
Environment.GetFolderPath(Environment.SpecialFolder.Startup); // Startup
Environment.GetFolderPath(Environment.SpecialFolder.System); // System Folder
Environment.GetFolderPath(Environment.SpecialFolder.Templates); // Document Templates

Intercept page exit event

I have users who have not been completing all required data.

<cfset unloadCheck=0>//a ColdFusion precheck in my page generation to see if unload check is needed
var erMsg="";
<cfif q.myData eq "">
    <cfset unloadCheck=1>
        verify(); //function elsewhere that checks all fields and populates erMsg with error messages for any fail(s)
        if(erMsg=="") window.onbeforeunload = null; //all OK so let them pass
        else window.onbeforeunload = confirmExit(); //borrowed from Jantimon above;
<cfif unloadCheck><!--- if any are outstanding, set the error message and the unload alert --->
    window.onbeforeunload = confirmExit;
    function confirmExit() {return "Data is incomplete for this Case:"+erMsg;}

Word wrapping in phpstorm

You have to enable Soft Wraps. Find that option through this path.

View > Active Editor > Use Soft Wraps

wrap words in PhpStorm

Ant build failed: "Target "build..xml" does not exist"

Is this a problem Only when you run ant -d or ant -verbose, but works other times?

I noticed this error message line:

Could not load definitions from resource org/apache/tools/ant/antlib.xml. It could not be found.

The org/apache/tools/ant/antlib.xml file is embedded in the ant.jar. The ant command is really a shell script called ant or a batch script called ant.bat. If the environment variable ANT_HOME is not set, it will figure out where it's located by looking to see where the ant command itself is located.

Sometimes I've seen this where someone will move the ant shell/batch script to put it in their path, and have ANT_HOME either not set, or set incorrectly.

What platform are you on? Is this Windows or Unix/Linux/MacOS? If you're on Windows, check to see if %ANT_HOME% is set. If it is, make sure it's the right directory. Make sure you have set your PATH to include %ANT_HOME%/bin.

If you're on Unix, don't copy the ant shell script to an executable directory. Instead, make a symbolic link. I have a directory called /usr/local/bin where I put the command I want to override the commands in /bin and /usr/bin. My Ant is installed in /opt/ant-1.9.2, and I have a symbolic link from /opt/ant-1.9.2 to /opt/ant. Then, I have symbolic links from all commands in /opt/ant/bin to /usr/local/bin. The Ant shell script can detect the symbolic links and find the correct Ant HOME location.

Next, go to your Ant installation directory and look under the lib directory to make sure ant.jar is there, and that it contains org/apache/tools/ant/antlib.xml. You can use the jar tvf ant.jar command. The only thing I can emphasize is that you do have everything setup correctly. You have your Ant shell script in your PATH either because you included the bin directory of your Ant's HOME directory in your classpath, or (if you're on Unix/Linux/MacOS), you have that file symbolically linked to a directory in your PATH.

Make sure your JAVA_HOME is set correctly (on Unix, you can use the symbolic link trick to have the java command set it for you), and that you're using Java 1.5 or higher. Java 1.4 will no longer work with newer versions of Ant.

Also run ant -version and see what you get. You might get the same error as before which leads me to think you have something wrong.

Let me know what you find, and your OS, and I can give you directions on reinstalling Ant.

Default value for field in Django model

Set editable to False and default to your default value.

b = models.CharField(max_length=7, default='0000000', editable=False)

Also, your id field is unnecessary. Django will add it automatically.

Read only the first line of a file?

This should do it:

f = open('myfile.txt')
first = f.readline()

How to connect to LocalDb

I am totally unable to connect to localdb with any tool including MSSMA, sqlcmd, etc. You would think Microsoft would document this, but I find nothing on MSDN. I have v12 and tried (localdb)\v12.0 and that didn't work. Issuing the command sqllocaldb i MSSQLLocalDB shows that the local instance is running, but there is no way to connect to it.

c:\> sqllocaldb i MSSQLLocalDB
Name:               MSSQLLocalDB
Version:            12.0.2000.8
Shared name:
Owner:              CWOLF-PC\cwolf
Auto-create:        Yes
State:              Running
Last start time:    6/12/2014 8:34:11 AM
Instance pipe name: np:\\.\pipe\LOCALDB#C86052DD\tsql\query
c:\> sqlcmd -L

    ;UID:Login ID=?;PWD:Password=?;Trusted_Connection:Use Integrated Security=?;
*APP:AppName=?;*WSID:WorkStation ID=?;

I finally figured it out!! the connect string is (localdb)\MSSQLLocalDB, e.g.:

$ sqlcmd -S \(localdb\)\\MSSQLLocalDB
1> select 'hello!'
2> go


(1 rows affected)    

Set EditText cursor color

you can use code below in layout


How do I concatenate text in a query in sql server?

The only way would be to convert your text field into an nvarchar field.

Select Cast(notes as nvarchar(4000)) + 'SomeText'
From NotesTable a

Otherwise, I suggest doing the concatenation in your application.

How to navigate through textfields (Next / Done Buttons)

First set keyboard return key in xib, otherwise you can write code in viewdidload:

passWord.returnKeyType = UIReturnKeyNext;

-(BOOL)textFieldShouldReturn:(UITextField *)textField
    if(textField == eMail) {
        [textField resignFirstResponder];
        [userName becomeFirstResponder];
    if (textField==userName) {
        [textField resignFirstResponder];
        [passWord becomeFirstResponder];
    if (textField==passWord) {
        [textField resignFirstResponder];
        [country becomeFirstResponder];
    if (textField==country) {
        [textField resignFirstResponder];
    return YES;

Best practice to look up Java Enum

update: As GreenTurtle correctly remarked, the following is wrong

I would just write

boolean result = Arrays.asList(FooEnum.values()).contains("Foo");

This is possibly less performant than catching a runtime exception, but makes for much cleaner code. Catching such exceptions is always a bad idea, since it is prone to misdiagnosis. What happens when the retrieval of the compared value itself causes an IllegalArgumentException ? This would then be treaten like a non matching value for the enumerator.

Setting property 'source' to 'org.eclipse.jst.jee.server:JSFTut' did not find a matching property

This is not an error. This is a warning. The difference is pretty huge. This particular warning basically means that the <Context> element in Tomcat's server.xml contains an unknown attribute source and that Tomcat doesn't know what to do with this attribute and therefore will ignore it.

Eclipse WTP adds a custom attribute source to the project related <Context> element in the server.xml of Tomcat which identifies the source of the context (the actual project in the workspace which is deployed to the particular server). This way Eclipse can correlate the deployed webapplication with an project in the workspace. Since Tomcat version 6.0.16, any unspecified XML tags and attributes in the server.xml will produce a warning during Tomcat's startup, even though there is no DTD nor XSD for server.xml.

Just ignore it. Your web project is fine. It should run fine. This issue is completely unrelated to JSF.

How can I fix the 'Missing Cross-Origin Resource Sharing (CORS) Response Header' webfont issue?

I'm going to assume your host is using C-Panel - and that it's probably HostGator or GoDaddy. In both cases they use C-Panel (in fact, a lot of hosts do) to make the Server administration as easy as possible on you, the end user. Even if you are hosting through someone else - see if you can log in to some kind of admin panel and find an .htaccess file that you can edit. (Note: The period before just means that it's a "hidden" file/directory).

Once you find the htaccess file add the following line:

  1. Header set Access-Control-Allow-Origin "*" Just to see if it works. Warning: Do not use this line on a production server

It should work. If not, call your host and ask them why the line isn't working - they'll probably be able to help you quickly from there.

  1. Once you do have the above working change the * to the address of the requesting domain You may find an issue with canonical addressing (including the www) and if so you may need to configure your host for a redirect. That's a different and smaller bridge to cross though. You'll at least be in the right place.

How to pick a new color for each plotted line within a figure in matplotlib?


color_cycle was deprecated in 1.5 in favor of this generalization:

# cycler is a separate package extracted from matplotlib.
from cycler import cycler
import matplotlib.pyplot as plt

plt.rc('axes', prop_cycle=(cycler('color', ['r', 'g', 'b'])))
plt.plot([1, 2])
plt.plot([2, 3])
plt.plot([3, 4])
plt.plot([4, 5])
plt.plot([5, 6])

Also shown in the (now badly named) example: mentioned at:

Tested in matplotlib 1.5.1.

Fatal Error: Allowed Memory Size of 134217728 Bytes Exhausted (CodeIgniter + XML-RPC)

If you're running a WHM-powered VPS (virtual private server) you may find that you do not have permissions to edit PHP.INI directly; the system must do it. In the WHM host control panel, go to Service ConfigurationPHP Configuration Editor and modify memory_limit:

Updating memory_limit on WHM 11.48.4

Understanding React-Redux and mapStateToProps()

React-Redux connect is used to update store for every actions.

import { connect } from 'react-redux';

const AppContainer = connect(  

export default AppContainer;

It's very simply and clearly explained in this blog.

You can clone github project or copy paste the code from that blog to understand the Redux connect.

Linux command-line call not returning what it should from os.system?

This is an old thread, but purely using os.system, the following's a valid way of accessing the data returned by the ps call. Note: it does use a pipe to write the data to a file on disk. And OP didn't specifically ask for a solution using os.system.

>>> os.system("ps > ~/Documents/ps.txt")
0    #system call is processed.
>>> os.system("cat ~/Documents/ps.txt")
  PID TTY          TIME CMD
 9927 pts/0    00:00:00 bash
10063 pts/0    00:00:00 python
12654 pts/0    00:00:00 sh
12655 pts/0    00:00:00 ps


>>> os.system("ps -p 10063 -o time --no-headers > ~/Documents/ps.txt")
>>> os.system("cat ~/Documents/ps.txt")

No idea why they are all returning zeroes though.

How to get full path of a file?

You may use this function. If the file name is given without relative path, then it is assumed to be present in the current working directory:

abspath() { old=`pwd`;new=$(dirname "$1");if [ "$new" != "." ]; then cd $new; fi;file=`pwd`/$(basename "$1");cd $old;echo $file; }


$ abspath file.txt

Usage with relative path:

$ abspath ../../some/dir/some-file.txt

With spaces in file name:

$ abspath "../../some/dir/another file.txt"
/I/am/in/some/dir/another file.txt

Convert array of JSON object strings to array of JS objects

var json = jQuery.parseJSON(s); //If you have jQuery.

Since the comment looks cluttered, please use the parse function after enclosing those square brackets inside the quotes.

var s=['{"Select":"11","PhotoCount":"12"}','{"Select":"21","PhotoCount":"22"}'];

Change the above code to

var s='[{"Select":"11","PhotoCount":"12"},{"Select":"21","PhotoCount":"22"}]';


$(document).ready(function() {
    var s= '[{"Select":"11","PhotoCount":"12"},{"Select":"21","PhotoCount":"22"}]';

    s = jQuery.parseJSON(s);

    alert( s[0]["Select"] );

And then use the parse function. It'll surely work.

EDIT :Extremely sorry that I gave the wrong function name. it's jQuery.parseJSON


The json api

Edit (30 April 2020):

Editing since I got an upvote for this answer. There's a browser native function available instead of JQuery (for nonJQuery users), JSON.parse("<json string here>")

Get position/offset of element relative to a parent container?

I got another Solution. Subtract parent property value from child property value

$('child-div').offset().top - $('parent-div').offset().top;

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

You have to add options also in allowed headers. browser sends a preflight request before original request is sent. See below

 res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE,PATCH,OPTIONS');

From source

In CORS, a preflight request with the OPTIONS method is sent, so that the server can respond whether it is acceptable to send the request with these parameters. The Access-Control-Request-Method header notifies the server as part of a preflight request that when the actual request is sent, it will be sent with a POST request method. The Access-Control-Request-Headers header notifies the server that when the actual request is sent, it will be sent with a X-PINGOTHER and Content-Type custom headers. The server now has an opportunity to determine whether it wishes to accept a request under these circumstances.


You can avoid this manual configuration by using npm package.I have used this method also, it is clear and easy.

How to make a shape with left-top round rounded corner and left-bottom rounded corner?

try this

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="">
<solid android:color="@color/upkia"/>
<corners android:radius="10dp"
    android:bottomRightRadius="0dp" />

How to convert CLOB to VARCHAR2 inside oracle pl/sql

Converting VARCHAR2 to CLOB

In PL/SQL a CLOB can be converted to a VARCHAR2 with a simple assignment, SUBSTR, and other methods. A simple assignment will only work if the CLOB is less then or equal to the size of the VARCHAR2. The limit is 32767 in PL/SQL and 4000 in SQL (although 12c allows 32767 in SQL).

For example, this code converts a small CLOB through a simple assignment and then coverts the beginning of a larger CLOB.

    v_small_clob clob := lpad('0', 1000, '0');
    v_large_clob clob := lpad('0', 32767, '0') || lpad('0', 32767, '0');
    v_varchar2   varchar2(32767);
    v_varchar2 := v_small_clob;
    v_varchar2 := substr(v_large_clob, 1, 32767);


The above code does not convert the value to a LONG. It merely looks that way because of limitations with PL/SQL debuggers and strings over 999 characters long.

For example, in PL/SQL Developer, open a Test window and add and debug the above code. Right-click on v_varchar2 and select "Add variable to Watches". Step through the code and the value will be set to "(Long Value)". There is a ... next to the text but it does not display the contents. PLSQL Developer Long Value


I suspect the real problem here is with C# but I don't know how enough about C# to debug the problem.

How do I get the width and height of a HTML5 canvas?

I had a problem because my canvas was inside of a container without ID so I used this jquery code below

$('.cropArea canvas').width()

Jquery Ajax, return success/error from controller

    type: "POST",
    data: formData,
    url: "/Forms/GetJobData",
    dataType: 'json',
    contentType: false,
    processData: false,               
    success: function (response) {
        if (response.success) {
        } else {
            // DoSomethingElse()
    error: function (response) {
        alert("error!");  // 



public ActionResult GetJobData(Jobs jobData)
    var mimeType = jobData.File.ContentType;
    var isFileSupported = IsFileSupported(mimeType);

    if (!isFileSupported){        
         //  Send "false"
        return Json(new { success = false, responseText = "The attached file is not supported." }, JsonRequestBehavior.AllowGet);
        //  Send "Success"
        return Json(new { success = true, responseText= "Your message successfuly sent!"}, JsonRequestBehavior.AllowGet);


basically you can send multiple parameters this way:


 return Json(new { 
                success = true,
                Name = model.Name,
                Phone = model.Phone,
                Email = model.Email                                


                type: "POST",
                url: '@Url.Action("GetData")',
                contentType: 'application/json; charset=utf-8',            
                success: function (response) {


                error: function (response) {

What Java ORM do you prefer, and why?

Hibernate, because it's basically the defacto standard in Java and was one of the driving forces in the creation of the JPA. It's got excellent support in Spring, and almost every Java framework supports it. Finally, GORM is a really cool wrapper around it doing dynamic finders and so on using Groovy.

It's even been ported to .NET (NHibernate) so you can use it there too.

Execute a command line binary with Node.js

You are looking for child_process.exec

Here is the example:

const exec = require('child_process').exec;
const child = exec('cat *.js bad_file | wc -l',
    (error, stdout, stderr) => {
        console.log(`stdout: ${stdout}`);
        console.log(`stderr: ${stderr}`);
        if (error !== null) {
            console.log(`exec error: ${error}`);

What is logits, softmax and softmax_cross_entropy_with_logits?

tf.nn.softmax computes the forward propagation through a softmax layer. You use it during evaluation of the model when you compute the probabilities that the model outputs.

tf.nn.softmax_cross_entropy_with_logits computes the cost for a softmax layer. It is only used during training.

The logits are the unnormalized log probabilities output the model (the values output before the softmax normalization is applied to them).

How to move or copy files listed by 'find' command in unix?

find /PATH/TO/YOUR/FILES -name NAME.EXT -exec cp -rfp {} /DST_DIR \;

Most efficient way to find smallest of 3 numbers Java?

Use the Arrays.sort() method, the lowest value will be element0.

In terms of performance, this should not be expensive since the sort operation is already optimised. Also has the advantage of being concise.

private int min(int ... value) {
    return value[0];

Proof of concept

    int[] intArr = {12, 5, 6, 9, 44, 28, 1, 4, 18, 2, 66, 13, 1, 33, 74, 12, 
    5, 6, 9, 44, 28, 1, 4, 18, 2, 66, 13};

    // Sorting approach
    long startTime = System.currentTimeMillis();
    int minVal = min(intArr);
    long endTime = System.currentTimeMillis();
    System.out.println("Sorting: Min => " + minVal + " took => " + (endTime - 
    System.out.println(startTime + "   "  + endTime);
    System.out.println(" ");

    // Scanning approach
    minVal = 100;
    startTime = System.currentTimeMillis();
    for(int val : intArr) {
        if (val < minVal)
            minVal = val;
    endTime = System.currentTimeMillis();
    System.out.println("Iterating: Min => " + minVal + " took => " + (endTime 
    - startTime));
    System.out.println(startTime + "   "  + endTime);

enter image description here

Object cannot be cast from DBNull to other types

I suspect that the line

DataTO.Id = Convert.ToInt64(dataAccCom.GetParameterValue(IDbCmd, "op_Id"));

is causing the problem. Is it possible that the op_Id value is being set to null by the stored procedure?

To Guard against it use the Convert.IsDBNull method. For example:

if (!Convert.IsDBNull(dataAccCom.GetParameterValue(IDbCmd, "op_Id"))
 DataTO.Id = Convert.ToInt64(dataAccCom.GetParameterValue(IDbCmd, "op_Id"));
 DataTO.Id = ...some default value or perform some error case management

Angular.js: set element height on page load

My solution if your ng-grid depend of element parent(div, layout) :


myapp.directive('sizeelement', function ($window) {
    priority: 0,
    link: function (scope, element) {
        scope.$watch(function(){return $(element).height(); }, function(newValue, oldValue) {

sample html

<div class="portlet  box grey" style="height: 100%" sizeelement>
    <div class="portlet-title">
        <h4><i class="icon-list"></i>Articles</h4>
    <div class="portlet-body" style="height:{{height-34}}px">
        <div class="gridStyle" ng-grid="gridOrderLine" ="min-height: 250px;"></div>

height-34 : 34 is fix height of my title div, you can fix other height.

It is easy directive but it work fine.

How can I force division to be floating point? Division keeps rounding down to 0?

If you want to use "true" (floating point) division by default, there is a command line flag:

python -Q new

There are some drawbacks (from the PEP):

It has been argued that a command line option to change the default is evil. It can certainly be dangerous in the wrong hands: for example, it would be impossible to combine a 3rd party library package that requires -Qnew with another one that requires -Qold.

You can learn more about the other flags values that change / warn-about the behavior of division by looking at the python man page.

For full details on division changes read: PEP 238 -- Changing the Division Operator

If condition inside of map() React

You're mixing if statement with a ternary expression, that's why you're having a syntax error. It might be easier for you to understand what's going on if you extract mapping function outside of your render method:

renderItem = (id) => {
    // just standard if statement
    if (this.props.schema.collectionName.length < 0) {
        return (
    return (

Then just call it when mapping:

render() {
    return (
            <div className="box">
                            id =>
                            // note: this is only passed when in top level of document
                            ] === this.props.parentDocumentId

Of course, you could have used the ternary expression as well, it's a matter of preference. What you use, however, affects the readability, so make sure to check different ways and tips to properly do conditional rendering in react and react native.

How to set a background image in Xcode using swift?


view.layer.contents = #imageLiteral(resourceName: "webbg").cgImage

How to encode text to base64 in python

It looks it's essential to call decode() function to make use of actual string data even after calling base64.b64decode over base64 encoded string. Because never forget it always return bytes literals.

import base64
conv_bytes = bytes('your string', 'utf-8')
print(conv_bytes)                                 # b'your string'
encoded_str = base64.b64encode(conv_bytes)
print(encoded_str)                                # b'eW91ciBzdHJpbmc='
print(base64.b64decode(encoded_str))              # b'your string'
print(base64.b64decode(encoded_str).decode())     # your string

Extract hostname name from string

Here's the jQuery one-liner:

$('<a>').attr('href', url).prop('hostname');

Serial Port (RS -232) Connection in C++

For the answer above, the default serial port is

        serialParams.BaudRate = 9600;
        serialParams.ByteSize = 8;
        serialParams.StopBits = TWOSTOPBITS;
        serialParams.Parity = NOPARITY;

How to change XML Attribute

Here's the beginnings of a parser class to get you started. This ended up being my solution to a similar problem:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml.Linq;

namespace XML
    public class Parser

        private string _FilePath = string.Empty;

        private XDocument _XML_Doc = null;

        public Parser(string filePath)
            _FilePath = filePath;
            _XML_Doc = XDocument.Load(_FilePath);

        /// <summary>
        /// Replaces values of all attributes of a given name (attributeName) with the specified new value (newValue) in all elements.
        /// </summary>
        /// <param name="attributeName"></param>
        /// <param name="newValue"></param>
        public void ReplaceAtrribute(string attributeName, string newValue)
            ReplaceAtrribute(string.Empty, attributeName, new List<string> { }, newValue);

        /// <summary>
        /// Replaces values of all attributes of a given name (attributeName) with the specified new value (newValue) in elements with a given name (elementName).
        /// </summary>
        /// <param name="elementName"></param>
        /// <param name="attributeName"></param>
        /// <param name="newValue"></param>
        public void ReplaceAtrribute(string elementName, string attributeName, string newValue)
            ReplaceAtrribute(elementName, attributeName, new List<string> { }, newValue);

        /// <summary>
        /// Replaces values of all attributes of a given name (attributeName) and value (oldValue)  
        /// with the specified new value (newValue) in elements with a given name (elementName).
        /// </summary>
        /// <param name="elementName"></param>
        /// <param name="attributeName"></param>
        /// <param name="oldValue"></param>
        /// <param name="newValue"></param>
        public void ReplaceAtrribute(string elementName, string attributeName, string oldValue, string newValue)
            ReplaceAtrribute(elementName, attributeName, new List<string> { oldValue }, newValue);              

        /// <summary>
        /// Replaces values of all attributes of a given name (attributeName), which has one of a list of values (oldValues), 
        /// with the specified new value (newValue) in elements with a given name (elementName).
        /// If oldValues is empty then oldValues will be ignored.
        /// </summary>
        /// <param name="elementName"></param>
        /// <param name="attributeName"></param>
        /// <param name="oldValues"></param>
        /// <param name="newValue"></param>
        public void ReplaceAtrribute(string elementName, string attributeName, List<string> oldValues, string newValue)
            List<XElement> elements = _XML_Doc.Elements().Descendants().ToList();

            foreach (XElement element in elements)
                if (elementName == string.Empty | element.Name.LocalName.ToString() == elementName)
                    if (element.Attribute(attributeName) != null)

                        if (oldValues.Count == 0 || oldValues.Contains(element.Attribute(attributeName).Value))
                        { element.Attribute(attributeName).Value = newValue; }


        public void SaveChangesToFile()


How to create python bytes object from long hex string?

You can do this with the hex codec. ie:

>>> s='000000000000484240FA063DE5D0B744ADBED63A81FAEA390000C8428640A43D5005BD44'
>>> s.decode('hex')

Compare two columns using pandas

You could use apply() and do something like this

df['que'] = df.apply(lambda x : x['one'] if x['one'] >= x['two'] and x['one'] <= x['three'] else "", axis=1)

or if you prefer not to use a lambda

def que(x):
    if x['one'] >= x['two'] and x['one'] <= x['three']:
        return x['one']
    return ''
df['que'] = df.apply(que, axis=1)

How can I find out the total physical memory (RAM) of my linux box suitable to be parsed by a shell script?

I find htop a useful tool.

sudo apt-get install htop

and then

free -m

will give the information you need.

What's a good way to extend Error in JavaScript?

The way to do this right is to return the result of the apply from the constructor, as well as setting the prototype in the usual complicated javascripty way:

function MyError() {
    var tmp = Error.apply(this, arguments); = = 'MyError'

    this.stack = tmp.stack
    this.message = tmp.message

    return this
    var IntermediateInheritor = function() {}
        IntermediateInheritor.prototype = Error.prototype;
    MyError.prototype = new IntermediateInheritor()

var myError = new MyError("message");
console.log("The message is: '"+myError.message+"'") // The message is: 'message'
console.log(myError instanceof Error)                // true
console.log(myError instanceof MyError)              // true
console.log(myError.toString())                      // MyError: message
console.log(myError.stack)                           // MyError: message \n 
                                                     // <stack trace ...>

The only problems with this way of doing it at this point (i've iterated it a bit) are that

  • properties other than stack and message aren't included in MyError and
  • the stacktrace has an additional line that isn't really necessary.

The first problem could be fixed by iterating through all the non-enumerable properties of error using the trick in this answer: Is it possible to get the non-enumerable inherited property names of an object?, but this isn't supported by ie<9. The second problem could be solved by tearing out that line in the stack trace, but I'm not sure how to safely do that (maybe just removing the second line of e.stack.toString() ??).

Class Not Found: Empty Test Suite in IntelliJ

Mark your package/directory as Test Sources in your IntelliJ IDEA.

MyISAM versus InnoDB

InnoDB offers:

ACID transactions
row-level locking
foreign key constraints
automatic crash recovery
table compression (read/write)
spatial data types (no spatial indexes)

In InnoDB all data in a row except for TEXT and BLOB can occupy 8,000 bytes at most. No full text indexing is available for InnoDB. In InnoDB the COUNT(*)s (when WHERE, GROUP BY, or JOIN is not used) execute slower than in MyISAM because the row count is not stored internally. InnoDB stores both data and indexes in one file. InnoDB uses a buffer pool to cache both data and indexes.

MyISAM offers:

fast COUNT(*)s (when WHERE, GROUP BY, or JOIN is not used)
full text indexing
smaller disk footprint
very high table compression (read only)
spatial data types and indexes (R-tree)

MyISAM has table-level locking, but no row-level locking. No transactions. No automatic crash recovery, but it does offer repair table functionality. No foreign key constraints. MyISAM tables are generally more compact in size on disk when compared to InnoDB tables. MyISAM tables could be further highly reduced in size by compressing with myisampack if needed, but become read-only. MyISAM stores indexes in one file and data in another. MyISAM uses key buffers for caching indexes and leaves the data caching management to the operating system.

Overall I would recommend InnoDB for most purposes and MyISAM for specialized uses only. InnoDB is now the default engine in new MySQL versions.

Cannot find Microsoft.Office.Interop Visual Studio

If you're using Visual Studio 2015 and you're encountering this problem, you can install MS Office Developer Tools for VS2015 here.

Is there a simple, elegant way to define singletons?

I'm very unsure about this, but my project uses 'convention singletons' (not enforced singletons), that is, if I have a class called DataController, I define this in the same module:

_data_controller = None
def GetDataController():
    global _data_controller
    if _data_controller is None:
        _data_controller = DataController()
    return _data_controller

It is not elegant, since it's a full six lines. But all my singletons use this pattern, and it's at least very explicit (which is pythonic).

How to capture multiple repeated groups?

I think you need something like this....


Which in Python3 will return


How to find a hash key containing a matching value

Heres an easy way to do find the keys of a given value:

    clients = {

    p clients.rassoc("client_id"=>"2180")

...and to find the value of a given key:

    p clients.assoc("orange") 

it will give you the key-value pair.

Trying to use fetch and pass in mode: no-cors

If you are using Express as back-end you just have to install cors and import and use it in app.use(cors());. If it is not resolved then try switching ports. It will surely resolve after switching ports

Check if a string is a date value

This is how I solved this problem in an app I'm working on right now:

updated based on feedback from krillgar:

var isDate = function(date) {
    return (new Date(date) !== "Invalid Date") && !isNaN(new Date(date));

How to specify legend position in matplotlib in graph coordinates

In addition to @ImportanceOfBeingErnest's post, I use the following line to add a legend at an absolute position in a plot.


For unknown reasons, bbox_transform=fig.transFigure does not work with me.

Process.start: how to get the output?

How to launch a process (such as a bat file, perl script, console program) and have its standard output displayed on a windows form:

processCaller = new ProcessCaller(this);
//processCaller.FileName = @"..\..\hello.bat";
processCaller.FileName = @"commandline.exe";
processCaller.Arguments = "";
processCaller.StdErrReceived += new DataReceivedHandler(writeStreamInfo);
processCaller.StdOutReceived += new DataReceivedHandler(writeStreamInfo);
processCaller.Completed += new EventHandler(processCompletedOrCanceled);
processCaller.Cancelled += new EventHandler(processCompletedOrCanceled);
// processCaller.Failed += no event handler for this one, yet.

this.richTextBox1.Text = "Started function.  Please stand by.." + Environment.NewLine;

// the following function starts a process and returns immediately,
// thus allowing the form to stay responsive.

You can find ProcessCaller on this link: Launching a process and displaying its standard output

Python pandas: how to specify data types when reading an Excel file?

Starting with v0.20.0, the dtype keyword argument in read_excel() function could be used to specify the data types that needs to be applied to the columns just like it exists for read_csv() case.

Using converters and dtype arguments together on the same column name would lead to the latter getting shadowed and the former gaining preferance.

1) Inorder for it to not interpret the dtypes but rather pass all the contents of it's columns as they were originally in the file before, we could set this arg to str or object so that we don't mess up our data. (one such case would be leading zeros in numbers which would be lost otherwise)

pd.read_excel('file_name.xlsx', dtype=str)            # (or) dtype=object

2) It even supports a dict mapping wherein the keys constitute the column names and values it's respective data type to be set especially when you want to alter the dtype for a subset of all the columns.

# Assuming data types for `a` and `b` columns to be altered
pd.read_excel('file_name.xlsx', dtype={'a': np.float64, 'b': np.int32})

Allow anything through CORS Policy

Use VSC or any other editor that has Live server, it will give you a proxy that will allow you to use GET or FETCH

How to call a method after a delay in Android

I prefer to use View.postDelayed() method, simple code below:

mView.postDelayed(new Runnable() {
    public void run() {
        // Do something after 1000 ms
}, 1000);

Button Listener for button in fragment in android

Try this :

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

public class FragmentOne extends Fragment{

    View rootView;        

public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

        rootView = inflater.inflate(R.layout.fragment_one, container, false);

        Button button = (Button) rootView.findViewById(;
        button.setOnClickListener(new View.OnClickListener()
            public void onClick(View v)
        return rootView;

  public void onButtonClicked(View view)
          //do your stuff here..           
    final FragmentTransaction ft = getFragmentManager().beginTransaction(); 
    ft.replace(, new FragmentTwo(), "NewFragmentTag"); 


check this : click here

How to return multiple objects from a Java method?

I noticed there is no no-custom class, n-length, no-cast, type-safe answers yet to returning multiple values.

Here is my go:

import java.util.Objects;

public final class NTuple<V, T extends  NTuple<?, ?>> {
    private final V value;
    private final T next;

    private NTuple(V value, T next) {
        this.value = value; = next;

    public static <V> NTuple<V, ?> of(V value) {
        return new NTuple<>(value, null);

    public static <V,  T extends  NTuple<?, ?>> NTuple<V, T> of(V value, T next) {
        return new NTuple<>(value, next);

    public V value() {
        return value;

    public T next() {
        return next;

    public static <V> V unpack0(NTuple<V, ?> tuple) {
        return Objects.requireNonNull(tuple, "0").value();

    public static <V, T extends NTuple<V, ?>> V unpack1(NTuple<?, T> tuple) {
        NTuple<?, T> tuple0 = Objects.requireNonNull(tuple, "0");
        NTuple<V, ?> tuple1 = Objects.requireNonNull(, "1");
        return tuple1.value();

    public static <V, T extends NTuple<?, NTuple<V, ?>>> V unpack2(NTuple<?, T> tuple) {
        NTuple<?, T> tuple0 = Objects.requireNonNull(tuple, "0");
        NTuple<?, NTuple<V, ?>> tuple1 = Objects.requireNonNull(, "1");
        NTuple<V, ?> tuple2 = Objects.requireNonNull(, "2");
        return tuple2.value();

Sample use:

public static void main(String[] args) {
    // pre-java 10 without lombok - use lombok's var or java 10's var if you can
    NTuple<String, NTuple<Integer, NTuple<Integer, ?>>> multiple = wordCount("hello world");
    String original = NTuple.unpack0(multiple);
    Integer wordCount = NTuple.unpack1(multiple);
    Integer characterCount  = NTuple.unpack2(multiple);

    System.out.println(original + ": " + wordCount + " words " + characterCount + " chars");

private static NTuple<String, NTuple<Integer, NTuple<Integer, ?>>> wordCount(String s) {
    int nWords = s.split(" ").length;
    int nChars = s.length();
    return NTuple.of(s, NTuple.of(nWords, NTuple.of(nChars)));


  • no-custom container class - no need to write a class just for a return type
  • n-length - can handle any number of return values
  • no-cast - no need to cast from Object
  • type-safe - the types are checked via Java's generics


  • inefficient for large numbers of return values
    • according to my experience with python's multiple return values, this should not happen in practice
  • heavy type declarations
    • can be alleviated by lombok/Java 10 var

How to validate GUID is a GUID



//Valid Guild


else {

// Invalid Guild


How to randomly pick an element from an array

You can also try this approach..

public static <E> E[] pickRandom_(int n,E ...item) {
        List<E> copy = Arrays.asList(item);
        if (copy.size() > n) {
            return (E[]) copy.subList(0, n).toArray();
        } else {
            return (E[]) copy.toArray();


How can I get session id in php and show it?

Before getting a session id you need to start a session and that is done by using: session_start() function.

Now that you have started a session you can get a session id by using: session_id().

/* A small piece of code for setting, displaying and destroying session in PHP */



/* now registering a session for an authenticated user */

/* now displaying the session id..... */
echo "the session id id: ".$r;
echo " and the session has been registered for: ".$_SESSION['username'];

/* now destroying the session id */

    echo "session destroyed...";

Scala: write string to file in one statement

If you like Groovy syntax, you can use the Pimp-My-Library design pattern to bring it to Scala:


class RichFile( file: File ) {

  def text = Source.fromFile( file )(Codec.UTF8).mkString

  def text_=( s: String ) {
    val out = new PrintWriter( file , "UTF-8")
    try{ out.print( s ) }
    finally{ out.close }

object RichFile {

  implicit def enrichFile( file: File ) = new RichFile( file )


It will work as expected:

scala> import RichFile.enrichFile
import RichFile.enrichFile

scala> val f = new File("/tmp/example.txt")
f: = /tmp/example.txt

scala> f.text = "hello world"

scala> f.text
res1: String = 
"hello world

Allow docker container to connect to a local/host postgres database


  1. Use as IP address range, not
  2. Don't use localhost to connect to the PostgreSQL database on your host, but the host's IP instead. To keep the container portable, start the container with the --add-host=database:<host-ip> flag and use database as hostname for connecting to PostgreSQL.
  3. Make sure PostgreSQL is configured to listen for connections on all IP addresses, not just on localhost. Look for the setting listen_addresses in PostgreSQL's configuration file, typically found in /etc/postgresql/9.3/main/postgresql.conf (credits to @DazmoNorton).

Long version is not a range of IP addresses, but a single address (namly No Docker container will ever get that address assigned, because it's the network address of the Docker bridge (docker0) interface.

When Docker starts, it will create a new bridge network interface, that you can easily see when calling ip a:

$ ip a
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN 
    link/ether 56:84:7a:fe:97:99 brd ff:ff:ff:ff:ff:ff
    inet scope global docker0
       valid_lft forever preferred_lft forever

As you can see, in my case, the docker0 interface has the IP address with a netmask of /16 (or This means that the network address is

The IP address is randomly assigned, but without any additional configuration, it will always be in the network. For each Docker container, a random address from that range will be assigned.

This means, if you want to grant access from all possible containers to your database, use

Eclipse IDE: How to zoom in on text?

Too late but it could be helpful :

Go to Window Menu > Preferences > General > Appearance > Colors and Fonts

then go to Java > Java Editor Text Font > Edit

Decreasing for loops in Python impossible?

for n in range(6,0,-1):
    print n

How to obtain Signing certificate fingerprint (SHA1) for OAuth 2.0 on Android?

Start an export process to create an apk for your app and use your production key. The very last page displays both your SHA1 and MD5 certificate fingerprints enter image description here

Why are empty catch blocks a bad idea?

It's probably never the right thing because you're silently passing every possible exception. If there's a specific exception you're expecting, then you should test for it, rethrow if it's not your exception.

    // Do some processing.
catch (FileNotFound fnf)
catch (Exception e)
    if (!IsGenericButExpected(e))

public bool IsGenericButExpected(Exception exception)
    var expected = false;
    if (exception.Message == "some expected message")
        // Handle gracefully ... ie. log or something.
        expected = true;

    return expected;

Iterate through Nested JavaScript Objects

var findObjectByLabel = function(obj, label) 
  var foundLabel=null;
  if(obj.label === label)
    return obj; 

for(var i in obj) 
        for(var j=0;j<obj[i].length;j++)
            foundLabel = findObjectByLabel(obj[i], label);
    else if(typeof(obj[i])  == 'object')
            foundLabel = findObjectByLabel(obj[i], label);     

        return foundLabel; 


return null;

var x = findObjectByLabel(cars, "Sedan");

How to find item with max value using linq?

With EF or LINQ to SQL:

var item = db.Items.OrderByDescending(i => i.Value).FirstOrDefault();

With LINQ to Objects I suggest to use morelinq extension MaxBy (get morelinq from nuget):

var item = items.MaxBy(i => i.Value);

Position absolute but relative to parent

If you don't give any position to parent then by default it takes static. If you want to understand that difference refer to this example

Example 1::



Here parent class has no position so element is placed according to body.

Example 2::


In this example parent has relative position hence element are positioned absolute inside relative parent.

How to set radio button checked as default in radiogroup?

    RadioGroup radioGroup = new RadioGroup(WvActivity.this);
    RadioButton radioBtn1 = new RadioButton(this);
    RadioButton radioBtn2 = new RadioButton(this);
    RadioButton radioBtn3 = new RadioButton(this);




PHP Date Time Current Time Add Minutes

I think one of the best solutions and easiest is:

strtotime("+30 minutes")

Maybe it's not the most efficient but is one of the more understandable.

Doing a cleanup action just before Node.js exits

Here's a nice hack for windows

process.on('exit', async () => {
    require('fs').writeFileSync('./tmp.js', 'crash', 'utf-8')

PHP Notice: Undefined offset: 1 with array when reading data

How to reproduce the above error in PHP:

php> $yarr = array(3 => 'c', 4 => 'd');

php> echo $yarr[4];

php> echo $yarr[1];
PHP Notice:  Undefined offset: 1 in 
/usr/local/lib/python2.7/dist-packages/phpsh/phpsh.php(578) : 
eval()'d code on line 1

What does that error message mean?

It means the php compiler looked for the key 1 and ran the hash against it and didn't find any value associated with it then said Undefined offset: 1

How do I make that error go away?

Ask the array if the key exists before returning its value like this:

php> echo array_key_exists(1, $yarr);

php> echo array_key_exists(4, $yarr);

If the array does not contain your key, don't ask for its value. Although this solution makes double-work for your program to "check if it's there" and then "go get it".

Alternative solution that's faster:

If getting a missing key is an exceptional circumstance caused by an error, it's faster to just get the value (as in echo $yarr[1];), and catch that offset error and handle it like this:

Simplest way to serve static data from outside the application server in a Java web application

If you want to work with JAX-RS (e.g. RESTEasy) try this:

public Response get(@QueryParam("url") final String url) {
    String picUrl = URLDecoder.decode(url, "UTF-8");

    return Response.ok(sendPicAsStream(picUrl))
            .header(HttpHeaders.CONTENT_TYPE, "image/jpg")

private StreamingOutput sendPicAsStream(String picUrl) {
    return output -> {
        try (InputStream is = (new URL(picUrl)).openStream()) {
            ByteStreams.copy(is, output);

using and

How to add a button dynamically using jquery

the $("body").append(r) statement should be within the test function, also there was misplaced " in the test method

function test() {
    var r=$('<input/>').attr({
        type: "button",
        id: "field",
        value: 'new'

Demo: Fiddle

In that case try a more jQuery-ish solution

<!DOCTYPE html>
        <script src=""></script>
        <script type="text/javascript">
              $('#mybutton').one('click', function(){
                  var r=$('<input/>').attr({
                      type: "button",
                      id: "field",
                      value: 'new'
        <button id="mybutton">Insert after</button> 

Demo: Plunker

How to use Selenium with Python?

You mean Selenium WebDriver? Huh....

Prerequisite: Install Python based on your OS

Install with following command

pip install -U selenium

And use this module in your code

from selenium import webdriver

You can also use many of the following as required

from import By
from import Select
from selenium.common.exceptions import NoSuchElementException

Here is an updated answer

I would recommend you to run script without IDE... Here is my approach

  1. USE IDE to find xpath of object / element
  2. And use find_element_by_xpath().click()

An example below shows login page automation

#ScriptName :
from selenium import webdriver

#Following are optional required
from import By
from import Select
from selenium.common.exceptions import NoSuchElementException

baseurl = ""
username = "admin"
password = "admin"

xpaths = { 'usernameTxtBox' : "//input[@name='username']",
           'passwordTxtBox' : "//input[@name='password']",
           'submitButton' :   "//input[@name='login']"

mydriver = webdriver.Firefox()

#Clear Username TextBox if already allowed "Remember Me" 

#Write Username in Username TextBox

#Clear Password TextBox if already allowed "Remember Me" 

#Write Password in password TextBox

#Click Login button

There is an another way that you can find xpath of any object -

  1. Install Firebug and Firepath addons in firefox
  2. Open URL in Firefox
  3. Press F12 to open Firepath developer instance
  4. Select Firepath in below browser pane and chose select by "xpath"
  5. Move cursor of the mouse to element on webpage
  6. in the xpath textbox you will get xpath of an object/element.
  7. Copy Paste xpath to the script.

Run script -


You can also use a CSS selector instead of xpath. CSS selectors are slightly faster than xpath in most cases, and are usually preferred over xpath (if there isn't an ID attribute on the elements you're interacting with).

Firepath can also capture the object's locator as a CSS selector if you move your cursor to the object. You'll have to update your code to use the equivalent find by CSS selector method instead -


How to compute the sum and average of elements in an array?

I think we can do like

var k=elmt.reduce(function(a,b){return parseFloat(a+parseFloat(b));})
var avg=k/elmt.length; 

I am using parseFloat twice because when 1) you add (a)9+b("1") number then result will be "91" but we want addition. so i used parseFloat

2)When addition of (a)9+parseFloat("1") happen though result will be "10" but it will be in string which we don't want so again i used parseFloat.

I hope i am clear. Suggestions are welcome

What exactly is \r in C language?

'\r' is the carriage return character. The main times it would be useful are:

  1. When reading text in binary mode, or which may come from a foreign OS, you'll find (and probably want to discard) it due to CR/LF line-endings from Windows-format text files.

  2. When writing to an interactive terminal on stdout or stderr, '\r' can be used to move the cursor back to the beginning of the line, to overwrite it with new contents. This makes a nice primitive progress indicator.

The example code in your post is definitely a wrong way to use '\r'. It assumes a carriage return will precede the newline character at the end of a line entered, which is non-portable and only true on Windows. Instead the code should look for '\n' (newline), and discard any carriage return it finds before the newline. Or, it could use text mode and have the C library handle the translation (but text mode is ugly and probably should not be used).

What is the easiest way to initialize a std::vector with hardcoded elements?

In C++0x you will be able to do it in the same way that you did with an array, but not in the current standard.

With only language support you can use:

int tmp[] = { 10, 20, 30 };
std::vector<int> v( tmp, tmp+3 ); // use some utility to avoid hardcoding the size here

If you can add other libraries you could try boost::assignment:

vector<int> v = list_of(10)(20)(30);

To avoid hardcoding the size of an array:

// option 1, typesafe, not a compile time constant
template <typename T, std::size_t N>
inline std::size_t size_of_array( T (&)[N] ) {
   return N;
// option 2, not typesafe, compile time constant
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))

// option 3, typesafe, compile time constant
template <typename T, std::size_t N>
char (&sizeof_array( T(&)[N] ))[N];    // declared, undefined
#define ARRAY_SIZE(x) sizeof(sizeof_array(x))

Difference between OpenJDK and Adoptium/AdoptOpenJDK

In short:

  • OpenJDK has multiple meanings and can refer to:
    • free and open source implementation of the Java Platform, Standard Edition (Java SE)
    • open source repository — the Java source code aka OpenJDK project
    • prebuilt OpenJDK binaries maintained by Oracle
    • prebuilt OpenJDK binaries maintained by the OpenJDK community
  • AdoptOpenJDK — prebuilt OpenJDK binaries maintained by community (open source licensed)


Prebuilt OpenJDK (or distribution) — binaries, built from, provided as an archive or installer, offered for various platforms, with a possible support contract.

OpenJDK, the source repository (also called OpenJDK project) - is a Mercurial-based open source repository, hosted at The Java source code. The vast majority of Java features (from the VM and the core libraries to the compiler) are based solely on this source repository. Oracle have an alternate fork of this.

OpenJDK, the distribution (see the list of providers below) - is free as in beer and kind of free as in speech, but, you do not get to call Oracle if you have problems with it. There is no support contract. Furthermore, Oracle will only release updates to any OpenJDK (the distribution) version if that release is the most recent Java release, including LTS (long-term support) releases. The day Oracle releases OpenJDK (the distribution) version 12.0, even if there's a security issue with OpenJDK (the distribution) version 11.0, Oracle will not release an update for 11.0. Maintained solely by Oracle.

Some OpenJDK projects - such as OpenJDK 8 and OpenJDK 11 - are maintained by the OpenJDK community and provide releases for some OpenJDK versions for some platforms. The community members have taken responsibility for releasing fixes for security vulnerabilities in these OpenJDK versions.

AdoptOpenJDK, the distribution is very similar to Oracle's OpenJDK distribution (in that it is free, and it is a build produced by compiling the sources from the OpenJDK source repository). AdoptOpenJDK as an entity will not be backporting patches, i.e. there won't be an AdoptOpenJDK 'fork/version' that is materially different from upstream (except for some build script patches for things like Win32 support). Meaning, if members of the community (Oracle or others, but not AdoptOpenJDK as an entity) backport security fixes to updates of OpenJDK LTS versions, then AdoptOpenJDK will provide builds for those. Maintained by OpenJDK community.

OracleJDK - is yet another distribution. Starting with JDK12 there will be no free version of OracleJDK. Oracle's JDK distribution offering is intended for commercial support. You pay for this, but then you get to rely on Oracle for support. Unlike Oracle's OpenJDK offering, OracleJDK comes with longer support for LTS versions. As a developer you can get a free license for personal/development use only of this particular JDK, but that's mostly a red herring, as 'just the binary' is basically the same as the OpenJDK binary. I guess it means you can download security-patched versions of LTS JDKs from Oracle's websites as long as you promise not to use them commercially.

Note. It may be best to call the OpenJDK builds by Oracle the "Oracle OpenJDK builds".

Donald Smith, Java product manager at Oracle writes:

Ideally, we would simply refer to all Oracle JDK builds as the "Oracle JDK", either under the GPL or the commercial license, depending on your situation. However, for historical reasons, while the small remaining differences exist, we will refer to them separately as Oracle’s OpenJDK builds and the Oracle JDK.

OpenJDK Providers and Comparison

|     Provider      | Free Builds | Free Binary   | Extended | Commercial | Permissive |
|                   | from Source | Distributions | Updates  | Support    | License    |
| AdoptOpenJDK      |    Yes      |    Yes        |   Yes    |   No       |   Yes      |
| Amazon – Corretto |    Yes      |    Yes        |   Yes    |   No       |   Yes      |
| Azul Zulu         |    No       |    Yes        |   Yes    |   Yes      |   Yes      |
| BellSoft Liberica |    No       |    Yes        |   Yes    |   Yes      |   Yes      |
| IBM               |    No       |    No         |   Yes    |   Yes      |   Yes      |
| jClarity          |    No       |    No         |   Yes    |   Yes      |   Yes      |
| OpenJDK           |    Yes      |    Yes        |   Yes    |   No       |   Yes      |
| Oracle JDK        |    No       |    Yes        |   No**   |   Yes      |   No       |
| Oracle OpenJDK    |    Yes      |    Yes        |   No     |   No       |   Yes      |
| ojdkbuild         |    Yes      |    Yes        |   No     |   No       |   Yes      |
| RedHat            |    Yes      |    Yes        |   Yes    |   Yes      |   Yes      |
| SapMachine        |    Yes      |    Yes        |   Yes    |   Yes      |   Yes      |

Free Builds from Source - the distribution source code is publicly available and one can assemble its own build

Free Binary Distributions - the distribution binaries are publicly available for download and usage

Extended Updates - aka LTS (long-term support) - Public Updates beyond the 6-month release lifecycle

Commercial Support - some providers offer extended updates and customer support to paying customers, e.g. Oracle JDK (support details)

Permissive License - the distribution license is non-protective, e.g. Apache 2.0

Which Java Distribution Should I Use?

In the Sun/Oracle days, it was usually Sun/Oracle producing the proprietary downstream JDK distributions based on OpenJDK sources. Recently, Oracle had decided to do their own proprietary builds only with the commercial support attached. They graciously publish the OpenJDK builds as well on their site.

What is happening starting JDK 11 is the shift from single-vendor (Oracle) mindset to the mindset where you select a provider that gives you a distribution for the product, under the conditions you like: platforms they build for, frequency and promptness of releases, how support is structured, etc. If you don't trust any of existing vendors, you can even build OpenJDK yourself.

Each build of OpenJDK is usually made from the same original upstream source repository (OpenJDK “the project”). However each build is quite unique - $free or commercial, branded or unbranded, pure or bundled (e.g., BellSoft Liberica JDK offers bundled JavaFX, which was removed from Oracle builds starting JDK 11).

If no environment (e.g., Linux) and/or license requirement defines specific distribution and if you want the most standard JDK build, then probably the best option is to use OpenJDK by Oracle or AdoptOpenJDK.

Additional information

Time to look beyond Oracle's JDK by Stephen Colebourne

Java Is Still Free by Java Champions community (published on September 17, 2018)

Java is Still Free 2.0.0 by Java Champions community (published on March 3, 2019)

Aleksey Shipilev about JDK updates interview by Opsian (published on June 27, 2019)

How to center a Window in Java?

There's something really simple that you might be overlooking after trying to center the window using either setLocationRelativeTo(null) or setLocation(x,y) and it ends up being a little off center.

Make sure that you use either one of these methods after calling pack() because the you'll end up using the dimensions of the window itself to calculate where to place it on screen. Until pack() is called, the dimensions aren't what you'd think thus throwing off the calculations to center the window. Hope this helps.

Initializing a dictionary in python with a key value and no corresponding values

Based on the clarifying comment by @user2989027, I think a good solution is the following:

definition = ['apple', 'ball']
data = {'orange':1, 'pear':2, 'apple':3, 'ball':4}
my_data = {}
for k in definition:
  except KeyError:
print my_data

I tried not to do anything fancy here. I setup my data and an empty dictionary. I then loop through a list of strings that represent potential keys in my data dictionary. I copy each value from data to my_data, but consider the case where data may not have the key that I want.


I found that this error can now also occur when using the wrong signing config. As described here, Android 7.0 introduces a new signature scheme, V2. The V2 scheme signs the entire APK rather than just the JAR, as is done in the V1 scheme. If you sign with only V2, and attempt to install on a pre-7.0 target, you'll get this error since the JARs themselves are not signed and the pre-7.0 PackageManager cannot detect the presence of the V2 APK signature.

To be compatible with all target systems, make sure the APK is signed with both schemes by checking both signature version boxes in Android Studio's Generate Signed APK dialog as shown here:

enter image description here

If only 7.0 targets are anticipated, then there is no need to include the V1 signature.

Network tools that simulate slow network connection

My work uses this tool, and it seems quite good:

Best of luck.

Class JavaLaunchHelper is implemented in two places

I have found the other workaround: to exclude libinstrument.dylib from project path. To do so, go to the Preferences -> Build, Execution and Deployment -> Compiler -> Excludes -> + and here add file by the path in error message.

Curl setting Content-Type incorrectly

I think you want to specify

-H "Content-Type:text/xml"

with a colon, not an equals.

Split string based on regex

I suggest

l = re.compile("(?<!^)\s+(?=[A-Z])(?!.\s)").split(s)

Check this demo.

Hamcrest compare collections

To compare two lists with the order preserved use,

assertThat(actualList, contains("item1","item2"));

Nullable types: better way to check for null or zero in c#

I agree with using the ?? operator.

If you're dealing with strings use if(String.IsNullOrEmpty(myStr))

Tomcat: java.lang.IllegalArgumentException: Invalid character found in method name. HTTP method names must be tokens

I know this is an old thread, but there is a particular case when this may happen:

If you are using AWS api gateway coupled with a VPC link, and if the Network Load Balancer has proxy protocol v2 enabled, a 400 Bad Request will happen as well.

Took me the whole afternoon to figure it out, so if it may help someone I'd be glad :)

Remove characters from a string

I know this is old but if you do a split then join it will remove all occurrences of a particular character ie:

var str = theText.split('A').join('')

will remove all occurrences of 'A' from the string, obviously it's not case sensitive

Delete duplicate records from a SQL table without a primary key

delete sub from (select ROW_NUMBER() OVer(Partition by empid order by empid)cnt from employee)sub where sub.cnt>1

Make a bucket public in Amazon S3

Amazon provides a policy generator tool:

After that, you can enter the policy requirements for the bucket on the AWS console:

How can I get column names from a table in SQL Server?

select *
where TABLE_NAME='tableName'

This is better than getting from sys.columns because it shows DATA_TYPE directly.

PostgreSQL query to list all table names?

Open up the postgres terminal with the databse you would like:

psql dbname (run this line in a terminal)

then, run this command in the postgres environment


This will describe all tables by name. Basically a list of tables by name ascending.

Then you can try this to describe a table by fields:

\d tablename.

Hope this helps.

forEach is not a function error with JavaScript array

parent.children is not an array. It is HTMLCollection and it does not have forEach method. You can convert it to the array first. For example in ES6:

Array.from(parent.children).forEach(child => {

or using spread operator:

[...parent.children].forEach(function (child) {

How to determine the Boost version on a system?

Might be already answered, but you can try this simple program to determine if and what installation of boost you have :

using namespace std;
int main()
return 0;

How do I set a fixed background image for a PHP file?

Your question doesn't have anything to do with PHP... just CSS.

Your CSS is correct, but your browser won't typically be able to open what you have put in for a URL. At a minimum, you'll need a file: path. It would be best to reference the file by its relative path.

Convert string to datetime in

As an alternative, if you put a space between the date and time, DateTime.Parse will recognize the format for you. That's about as simple as you can get it. (If ParseExact was still not being recognized)

How to hide axes and gridlines in Matplotlib (python)

# Hide grid lines

# Hide axes ticks

Note, you need matplotlib>=1.2 for set_zticks() to work.

Getting Data from Android Play Store

I've coded a small Node.js module to scrape app and list data from Google Play: google-play-scraper

var gplay = require('google-play-scrapper');

    category: gplay.category.GAME_ACTION,
    collection: gplay.collection.TOP_FREE,
    num: 2


 [ { url: '',
    appId: 'com.playappking.busrush',
    title: 'Bus Rush',
    developer: 'Play App King',
    icon: '',
    score: 3.9,
    price: '0',
    free: false },
  { url: '',
    appId: 'com.yodo1.crossyroad',
    title: 'Crossy Road',
    developer: 'Yodo1 Games',
    icon: '',
    score: 4.5,
    price: '0',
    free: false } ]

Getting indices of True values in a boolean list

You can use filter for it:

filter(lambda x: self.states[x], range(len(self.states)))

The range here enumerates elements of your list and since we want only those where self.states is True, we are applying a filter based on this condition.

For Python > 3.0:

list(filter(lambda x: self.states[x], range(len(self.states))))

add a temporary column with a value

select field1, field2, NewField = 'example' from table1 

Waiting till the async task finish its work

AsyncTask have four methods..

onPreExecute  -- for doing something before calling background task in Async

doInBackground  -- operation/Task to do in Background

onProgressUpdate  -- it is for progress Update

onPostExecute  -- this method calls after asyncTask return from doInBackground.

you can call your work on onPostExecute() it calls after returning from doInBackground()

onPostExecute is what you need to Implement.

$(...).datepicker is not a function - JQuery - Bootstrap

To get rid of the bad looking datepicker you need to add jquery-ui css

<link rel="stylesheet" type="text/css" href="">

Determine if $.ajax error is a timeout

If your error event handler takes the three arguments (xmlhttprequest, textstatus, and message) when a timeout happens, the status arg will be 'timeout'.

Per the jQuery documentation:

Possible values for the second argument (besides null) are "timeout", "error", "notmodified" and "parsererror".

You can handle your error accordingly then.

I created this fiddle that demonstrates this.

    url: "/ajax_json_echo/",
    type: "GET",
    dataType: "json",
    timeout: 1000,
    success: function(response) { alert(response); },
    error: function(xmlhttprequest, textstatus, message) {
        if(textstatus==="timeout") {
            alert("got timeout");
        } else {

With jsFiddle, you can test ajax calls -- it will wait 2 seconds before responding. I put the timeout setting at 1 second, so it should error out and pass back a textstatus of 'timeout' to the error handler.

Hope this helps!

Reset par to the default values at startup is the best function, but it clears also all plots. If you want to keep plots in your window, at the beginning save default par settings:

def.par = par()

Then when you use your par functions you still have a backup of default par settings. Later on, after generating plots, finish with:

par(def.par) #go back to default par settings

With this, you keep generated plots and reset par settings.

nodejs - How to read and output jpg image?

Here is how you can read the entire file contents, and if done successfully, start a webserver which displays the JPG image in response to every request:

var http = require('http')
var fs = require('fs')

fs.readFile('image.jpg', function(err, data) {
  if (err) throw err // Fail if the file can't be read.
  http.createServer(function(req, res) {
    res.writeHead(200, {'Content-Type': 'image/jpeg'})
    res.end(data) // Send the file data to the browser.
  console.log('Server running at http://localhost:8124/')

Note that the server is launched by the "readFile" callback function and the response header has Content-Type: image/jpeg.

[Edit] You could even embed the image in an HTML page directly by using an <img> with a data URI source. For example:

  res.writeHead(200, {'Content-Type': 'text/html'});
  res.write('<html><body><img src="data:image/jpeg;base64,')

How to disassemble a binary executable in Linux to get the assembly code?

You can come pretty damn close (but no cigar) to generating assembly that will reassemble, if that's what you are intending to do, using this rather crude and tediously long pipeline trick (replace /bin/bash with the file you intend to disassemble and bash.S with what you intend to send the output to):

objdump --no-show-raw-insn -Matt,att-mnemonic -Dz /bin/bash | grep -v "file format" | grep -v "(bad)" | sed '1,4d' | cut -d' ' -f2- | cut -d '<' -f2 | tr -d '>' | cut -f2- | sed -e "s/of\ section/#Disassembly\ of\ section/" | grep -v "\.\.\." > bash.S

Note how long this is, however. I really wish there was a better way (or, for that matter, a disassembler capable of outputting code that an assembler will recognize), but unfortunately there isn't.

How to convert a single char into an int

The answers provided are great as long as you only want to handle Arabic numerals, and are working in an encoding where those numerals are sequential, and in the same place as ASCII.

This is almost always the case.

If it isn't then you need a proper library to help you.

Let's start with ICU.

  1. First convert the byte-string to a unicode string. (Left as an exercise for the reader).
  2. Then use uchar.h to look at each character.
  3. if we the character is UBool u_isdigit (UChar32 c)
  4. then the value is int32_t u_charDigitValue ( UChar32 c )

Or maybe ICU has some function to do it for you - I haven't looked at it in detail.

Making interface implementations async

Better solution is to introduce another interface for async operations. New interface must inherit from original interface.


interface IIO
    void DoOperation();

interface IIOAsync : IIO
    Task DoOperationAsync();

class ClsAsync : IIOAsync
    public void DoOperation()

    public async Task DoOperationAsync()
        //just an async code demo
        await Task.Delay(1000);

class Program
    static void Main(string[] args)
        IIOAsync asAsync = new ClsAsync();
        IIO asSync = asAsync;


        Console.WriteLine("After call to sync func using Async iface: {0}", 

        Console.WriteLine("After call to async func using Async iface: {0}", 

        Console.WriteLine("After call to sync func using Sync iface: {0}", 


P.S. Redesign your async operations so they return Task instead of void, unless you really must return void.

Apache shutdown unexpectedly

i think the error is here

[pid 5384:tid 240] AH01909: RSA certificate configured for does NOT include an ID which matches the server name

or there is another app are using the port 80 try restarting your computer and only opening apache and see what happens

or try on reinstalling apache or using Ampps

Using JQuery to check if no radio button in a group has been checked

if ($("input[name='html_elements']:checked").size()==0) {
   alert('Nothing is checked!');
else {
  alert('One of the radio buttons is checked!');

Using a SELECT statement within a WHERE clause

The principle of subqueries is not at all bad, but I don't think that you should use it in your example. If I understand correctly you want to get the maximum score for each date. In this case you should use a GROUP BY.

DateTime and CultureInfo

You may try the following:

System.Globalization.CultureInfo cultureinfo =
        new System.Globalization.CultureInfo("nl-NL");
DateTime dt = DateTime.Parse(date, cultureinfo);

jQuery: how to change title of document during .ready()?

<script type="text/javascript">
$(document).ready(function() {

    $(this).attr("title", "sometitle");


bootstrap.min.js:6 Uncaught Error: Bootstrap dropdown require Popper.js

include popper.js before bootstrap.min.js

<script src=""></script>

use this link to get popper

Validating IPv4 addresses with regexp


Test to find matches in text,

Following are the rules defining the valid combinations in each number of an IP address:

  • Any one- or two-digit number.
  • Any three-digit number beginning with 1.

  • Any three-digit number beginning with 2 if the second digit is 0 through 4.

  • Any three-digit number beginning with 25 if the third digit is 0 through 5.

Let'start with (((25[0-5])|(2[0-4]\d)|(1\d{2})|(\d{1,2}))\.), a set of four nested subexpressions, and we’ll look at them in reverse order. (\d{1,2}) matches any one- or two-digit number or numbers 0 through 99. (1\d{2}) matches any three-digit number starting with 1 (1 followed by any two digits), or numbers 100 through 199. (2[0-4]\d) matches numbers 200 through 249. (25[0-5]) matches numbers 250 through 255. Each of these subexpressions is enclosed within another subexpression with an | between each (so that one of the four subexpressions has to match, not all). After the range of numbers comes \. to match ., and then the entire series (all the number options plus \.) is enclosed into yet another subexpression and repeated three times using {3}. Finally, the range of numbers is repeated (this time without the trailing \.) to match the final IP address number. By restricting each of the four numbers to values between 0 and 255, this pattern can indeed match valid IP addresses and reject invalid addresses.

Excerpt From: Ben Forta. “Learning Regular Expressions.”

If neither a character is wanted at the beginning of IP address nor at the end, ^ and $ metacharacters ought to be used, respectively.


Test to find matches in text,

multiple classes on single element html

It's a good practice if you need them. It's also a good practice is they make sense, so future coders can understand what you're doing.

But generally, no it's not a good practice to attach 10 class names to an object because most likely whatever you're using them for, you could accomplish the same thing with far fewer classes. Probably just 1 or 2.

To qualify that statement, javascript plugins and scripts may append far more classnames to do whatever it is they're going to do. Modernizr for example appends anywhere from 5 - 25 classes to your body tag, and there's a very good reason for it. jQuery UI appends lots of classnames when you use one of the widgets in that library.

Write in body request with HttpClient

Extending your code (assuming that the XML you want to send is in xmlString) :

String xmlString = "</xml>";
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpRequest = new HttpPost(this.url);
httpRequest.setHeader("Content-Type", "application/xml");
StringEntity xmlEntity = new StringEntity(xmlString);
httpRequest.setEntity(xmlEntity );
HttpResponse httpresponse = httpclient.execute(httppost);

Case insensitive regular expression without re.compile?

You can also perform case insensitive searches using search/match without the IGNORECASE flag (tested in Python 2.7.3):'(?i)test', 'TeSt').group()    ## returns 'TeSt'
re.match(r'(?i)test', 'TeSt').group()     ## returns 'TeSt'

PHP Change Array Keys

The solution to when you're using XMLWriter (native to PHP 5.2.x<) is using $xml->startElement('itemName'); this will replace the arrays key.

Windows equivalent to UNIX pwd

cd without any parameters is equivalent to pwd on Unix/Linux.

From the console output of typing cd /?:

Displays the name of or changes the current directory.


Type CD without parameters to display the current drive and directory.

Selenium -- How to wait until page is completely loaded

There are two different ways to use delay in selenium one which is most commonly in use. Please try this:

driver.manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);

second one which you can use that is simply try catch method by using that method you can get your desire result.if you want example code feel free to contact me defiantly I will provide related code

How to format LocalDate to string?

With the help of ProgrammersBlock posts I came up with this. My needs were slightly different. I needed to take a string and return it as a LocalDate object. I was handed code that was using the older Calendar and SimpleDateFormat. I wanted to make it a little more current. This is what I came up with.

    import java.time.LocalDate;
    import java.time.format.DateTimeFormatter;

    void ExampleFormatDate() {

    LocalDate formattedDate = null;  //Declare LocalDate variable to receive the formatted date.
    DateTimeFormatter dateTimeFormatter;  //Declare date formatter
    String rawDate = "2000-01-01";  //Test string that holds a date to format and parse.

    dateTimeFormatter = DateTimeFormatter.ISO_LOCAL_DATE;

    //formattedDate.parse(String string) wraps the String.format(String string, DateTimeFormatter format) method.
    //First, the rawDate string is formatted according to DateTimeFormatter.  Second, that formatted string is parsed into
    //the LocalDate formattedDate object.
    formattedDate = formattedDate.parse(String.format(rawDate, dateTimeFormatter));


Hopefully this will help someone, if anyone sees a better way of doing this task please add your input.

How to convert comma separated string into numeric array in javascript

The split() method is used to split a string into an array of substrings, and returns the new array.


arr =  strVale.split(',');


What is the difference between a static and const variable?

The short answer:

A const is a promise that you will not try to modify the value once set.

A static variable means that the object's lifetime is the entire execution of the program and it's value is initialized only once before the program startup. All statics are initialized if you do not explicitly set a value to them.The manner and timing of static initialization is unspecified.

C99 borrowed the use of const from C++. On the other hand, static has been the source of many debates (in both languages) because of its often confusing semantics.

Also, with C++0x until C++11 the use of the static keyword was deprecated for declaring objects in namespace scope. This deprecation was removed in C++11 for various reasons (see here).

The longer answer: More on the keywords than you wanted to know (right from the standards):


#include <fenv.h>

/* file scope, static storage, internal linkage */
static int i1; // tentative definition, internal linkage
extern int i1; // tentative definition, internal linkage

int i2; // external linkage, automatic duration (effectively lifetime of program)

int *p = (int []){2, 4}; // unnamed array has static storage

/* effect on string literals */
char *s = "/tmp/fileXXXXXX"; // static storage always, may not be modifiable
char *p = (char []){"/tmp/fileXXXXXX"}; // static, modifiable
const char *cp = (const char []){"/tmp/fileXXXXXX"}  // static, non-modifiable

void f(int m)
    static int vla[ m ]; // err

    float w[] = { 0.0/0.0 }; // raises an exception

    /* block scope, static storage, no-linkage */
    static float x = 0.0/0.0; // does not raise an exception
    /* ... */
     /* effect on string literals */
    char *s = "/tmp/fileXXXXXX"; // static storage always, may not be modifiable
    char *p = (char []){"/tmp/fileXXXXXX"}; // automatic storage, modifiable
    const char *cp = (const char []){"/tmp/fileXXXXXX"}  // automatic storage, non-modifiable


inline void bar(void)
     const static int x = 42; // ok
     // Note: Since an inline definition is distinct from the 
     // corresponding external definition and from any other
     // corresponding inline definitions in other translation 
     // units, all corresponding objects with static storage
     // duration are also distinct in each of the definitions
     static int y = -42; // error, inline function definition

// the last declaration also specifies that the argument 
// corresponding to a in any call to f must be a non-null 
// pointer to the first of at least three arrays of 5 doubles
void f(double a[static 3][5]);

static void g(void); // internal linkage


Has the same semantics mostly except as noted in the short answer. Also, there are no parameter qualifying statics.

extern "C" {
static void f4(); // the name of the function f4 has
                  // internal linkage (not C language
                  // linkage) and the function’s type
                  // has C language linkage.

class S {
   mutable static int i; // err
   mutable static int j; // err
   static int k; // ok, all instances share the same member

inline void bar(void)
     const static int x = 42; // ok
     static int y = -42; // ok

There are a few more nuances of C++'s static that I leave out here. Have a look at a book or the standard.

how to get text from textview

If it is the sum of all the numbers you want, I made a little snippet for you that can handle both + and - using a regex (I left some print-calls in there to help visualise what happens):

    final String string = "  " + 5 + "\n" + "-" + " " + 9+"\n"+"+"+" "+5; //Or get the value from a TextView
    final Pattern pattern = Pattern.compile("(-?).?(\\d+)");
    Matcher matcher = pattern.matcher(string);

    int sum = 0;

    while( matcher.find() ){
        sum += Integer.parseInt(;
    System.out.print("\nSum: "+sum);

This code prints the following:

- 9
+ 5

Sum: 1

Edit: sorry if I misunderstood your question, it was a little bit unclear what you wanted to do. I assumed you wanted to get the sum of the numbers as an integer rather than a string.

Edit2: to get the numbers separate from each other, do something like this instead:

    final String string = "  " + 5 + "\n" + "-" + " " + 9+"\n"+"+"+" "+5; //Or get the value from a TextView
    final Pattern pattern = Pattern.compile("(-?).?(\\d+)");
    Matcher matcher = pattern.matcher(string);
    ArrayList<Integer> numbers = new ArrayList<Integer>();

    while( matcher.find() ){

How do I find the time difference between two datetime objects in python?

>>> import datetime
>>> first_time =
>>> later_time =
>>> difference = later_time - first_time
>>> seconds_in_day = 24 * 60 * 60
datetime.timedelta(0, 8, 562000)
>>> divmod(difference.days * seconds_in_day + difference.seconds, 60)
(0, 8)      # 0 minutes, 8 seconds

Subtracting the later time from the first time difference = later_time - first_time creates a datetime object that only holds the difference. In the example above it is 0 minutes, 8 seconds and 562000 microseconds.

is the + operator less performant than StringBuffer.append()

Try this:

var s = ["<a href='", url, "'>click here</a>"].join("");

How do I make an asynchronous GET request in PHP?

file_get_contents will do what you want

$output = file_get_contents('');
echo $output;

Edit: One way to fire off a GET request and return immediately.

Quoted from

function curl_post_async($url, $params)
    foreach ($params as $key => &$val) {
      if (is_array($val)) $val = implode(',', $val);
        $post_params[] = $key.'='.urlencode($val);
    $post_string = implode('&', $post_params);


    $fp = fsockopen($parts['host'],
        $errno, $errstr, 30);

    $out = "POST ".$parts['path']." HTTP/1.1\r\n";
    $out.= "Host: ".$parts['host']."\r\n";
    $out.= "Content-Type: application/x-www-form-urlencoded\r\n";
    $out.= "Content-Length: ".strlen($post_string)."\r\n";
    $out.= "Connection: Close\r\n\r\n";
    if (isset($post_string)) $out.= $post_string;

    fwrite($fp, $out);

What this does is open a socket, fire off a get request, and immediately close the socket and return.

How to serialize an object to XML without getting xmlns="..."?

If you want to remove the namespace you may also want to remove the version, to save you searching I've added that functionality so the below code will do both.

I've also wrapped it in a generic method as I'm creating very large xml files which are too large to serialize in memory so I've broken my output file down and serialize it in smaller "chunks":

    public static string XmlSerialize<T>(T entity) where T : class
        // removes version
        XmlWriterSettings settings = new XmlWriterSettings();
        settings.OmitXmlDeclaration = true;

        XmlSerializer xsSubmit = new XmlSerializer(typeof(T));
        using (StringWriter sw = new StringWriter())
        using (XmlWriter writer = XmlWriter.Create(sw, settings))
            // removes namespace
            var xmlns = new XmlSerializerNamespaces();
            xmlns.Add(string.Empty, string.Empty);

            xsSubmit.Serialize(writer, entity, xmlns);
            return sw.ToString(); // Your XML

How to install python modules without root access?

Important question. The server I use (Ubuntu 12.04) had easy_install3 but not pip3. This is how I installed Pip and then other packages to my home folder

  1. Asked admin to install Ubuntu package python3-setuptools

  2. Installed pip

Like this:

 easy_install3 --prefix=$HOME/.local pip
 mkdir -p $HOME/.local/lib/python3.2/site-packages
 easy_install3 --prefix=$HOME/.local pip
  1. Add Pip (and other Python apps to path)

Like this:

echo PATH="$HOME/.local/bin:$PATH" > $HOME/.profile
  1. Install Python package

like this

pip3 install --user httpie

# test httpie package

Query to check index on a table

If you're using MySQL you can run SHOW KEYS FROM table or SHOW INDEXES FROM table

jQuery - How to dynamically add a validation rule

To validate all dynamically generated elements could add a special class to each of these elements and use each() function, something like

$("#DivIdContainer .classToValidate").each(function () {
    $(this).rules('add', {
        required: true

Composer killed while updating

composer 2 update have reduced the memory usage

composer self-update
composer update
composer require xxx

How to read multiple text files into a single RDD?

You can specify whole directories, use wildcards and even CSV of directories and wildcards. E.g.:


As Nick Chammas points out this is an exposure of Hadoop's FileInputFormat and therefore this also works with Hadoop (and Scalding).

Set folder for classpath

If you are using Java 6 or higher you can use wildcards of this form:

java -classpath ".;c:\mylibs\*;c:\extlibs\*" MyApp

If you would like to add all subdirectories: lib\a\, lib\b\, lib\c\, there is no mechanism for this in except:

java -classpath ".;c:\lib\a\*;c:\lib\b\*;c:\lib\c\*" MyApp

There is nothing like lib\*\* or lib\** wildcard for the kind of job you want to be done.

ASP.Net MVC: How to display a byte array image from model

One way is to add this to a new c# class or HtmlExtensions class

public static class HtmlExtensions
    public static MvcHtmlString Image(this HtmlHelper html, byte[] image)
        var img = String.Format("data:image/jpg;base64,{0}", Convert.ToBase64String(image));
        return new MvcHtmlString("<img src='" + img + "' />");

then you can do this in any view


Call a Class From another class

Class2 class2 = new Class2();

Instead of calling the main, perhaps you should call individual methods where and when you need them.

How to find out what is locking my tables?

For getting straight to "who is blocked/blocking" I combined/abbreviated sp_who and sp_lock into a single query which gives a nice overview of who has what object locked to what level.

--Create Procedure WhoLock
set nocount on
if object_id('tempdb..#locksummary') is not null Drop table #locksummary
if object_id('tempdb..#lock') is not null Drop table #lock
create table #lock (    spid int,    dbid int,    objId int,    indId int,    Type char(4),    resource nchar(32),    Mode char(8),    status char(6))
Insert into #lock exec sp_lock
if object_id('tempdb..#who') is not null Drop table #who
create table #who (     spid int, ecid int, status char(30),
            loginame char(128), hostname char(128),
            blk char(5), dbname char(128), cmd char(16)
            , request_id INT --Needed for SQL 2008 onwards
Insert into #who exec sp_who
Print '-----------------------------------------'
Print 'Lock Summary for ' + @@servername  + ' (excluding tempdb):'
Print '-----------------------------------------' + Char(10)
Select     left(loginame, 28) as loginame, 
    left(db_name(dbid),128) as DB,
    left(object_name(objID),30) as object,
    max(mode) as [ToLevel],
    Count(*) as [How Many],
    Max(Case When mode= 'X' Then cmd Else null End) as [Xclusive lock for command],
    l.spid, hostname
into #LockSummary
from #lock l join #who w on l.spid= w.spid
where dbID != db_id('tempdb') and l.status='GRANT'
group by dbID, objID, l.spid, hostname, loginame

Select * from #LockSummary order by [ToLevel] Desc, [How Many] Desc, loginame, DB, object

Print '--------'
Print 'Who is blocking:'
Print '--------' + char(10)
SELECT p.spid
,convert(char(12), db_name
, program_name
, p.loginame
, convert(char(12), hostname) hostname
, cmd
, p.status
, p.blocked
, login_time
, last_batch
, p.spid
FROM      master..sysprocesses p
JOIN      master..sysdatabases d ON p.dbid =  d.dbid
          FROM      master..sysprocesses p2
          WHERE     p2.blocked = p.spid )

Print '--------'
Print 'Details:'
Print '--------' + char(10)
Select     left(loginame, 30) as loginame,  l.spid,
    left(db_name(dbid),15) as DB,
    left(object_name(objID),40) as object,
    mode ,
from #lock l join #who w on l.spid= w.spid
where dbID != db_id('tempdb') and blk <>0
Order by mode desc, blk, loginame, dbID, objID, l.status

(For what the lock level abbreviations mean, see e.g.

Copied from: sp_WhoLock – a T-SQL stored proc combining sp_who and sp_lock...

NB the [Xclusive lock for command] column can be misleading -- it shows the current command for that spid; but the X lock could have been triggered by an earlier command in the transaction.

Converting Long to Date in Java returns 1970


java.time.Instant                    // Represent a moment as seen in UTC. Internally, a count of nanoseconds since 1970-01-01T00:00Z.
.ofEpochSecond( 1_220_227_200L )     // Pass a count of whole seconds since the same epoch reference of 1970-01-01T00:00Z.

Know Your Data

People use various precisions in tracking time as a number since an epoch. So when you obtain some numbers to be interpreted as a count since an epoch, you must determine:

  • What epoch?
    Many epochs dates have been used in various systems. Commonly used is POSIX/Unix time, where the epoch is the first moment of 1970 in UTC. But you should not assume this epoch.
  • What precision?
    Are we talking seconds, milliseconds, microseconds, or nanoseconds since the epoch?
  • What time zone?
    Usually a count since epoch is in UTC/GMT time zone, that is, has no time zone offset at all. But sometimes, when involving inexperienced or date-time ignorant programmers, there may be an implied time zone.

In your case, as others noted, you seem to have been given seconds since the Unix epoch. But you are passing those seconds to a constructor that expects milliseconds. So the solution is to multiply by 1,000.

Lessons learned:

  • Determine, don't assume, the meaning of received data.
  • Read the doc.

Graph showing various granularities of resolution in date-time systems including whole seconds, milliseconds, microseconds, and nanoseconds.

Your Data

Your data seems to be in whole seconds. If we assume an epoch of the beginning of 1970, and if we assume UTC time zone, then 1,220,227,200 is the first moment of the first day of September 2008.


The java.util.Date and .Calendar classes bundled with Java are notoriously troublesome. Avoid them. Use instead either the Joda-Time library or the new java.time package bundled in Java 8 (and inspired by Joda-Time).

Note that unlike j.u.Date, a DateTime in Joda-Time truly knows its own assigned time zone. So in the example Joda-Time 2.4 code seen below, note that we first parse the milliseconds using the default assumption of UTC. Then, secondly, we assign a time zone of Paris to adjust. Same moment in the timeline of the Universe, but different wall-clock time. For demonstration, we adjust again, to UTC. Almost always better to explicitly specify your desired/expected time zone rather than rely on an implicit default (often the cause of trouble in date-time work).

We need milliseconds to construct a DateTime. So take your input of seconds, and multiply by a thousand. Note that the result must be a 64-bit long as we would overflow a 32-bit int.

long input = 1_220_227_200L;  // Note the "L" appended to long integer literals.
long milliseconds = ( input * 1_000L ); // Use a "long", not the usual "int". Note the appended "L".

Feed that count of milliseconds to constructor. That particular constructor assumes the count is from the Unix epoch of 1970. So adjust time zone as desired, after construction.

Use proper time zone names, a combination of continent and city/region. Never use 3 or 4 letter codes such as EST as they are neither standardized not unique.

DateTime dateTimeParis = new DateTime( milliseconds ).withZone( DateTimeZone.forID( "Europe/Paris" ) );

For demonstration, adjust the time zone again.

DateTime dateTimeUtc = dateTimeParis.withZone( DateTimeZone.UTC );
DateTime dateTimeMontréal = dateTimeParis.withZone( DateTimeZone.forID( "America/Montreal" ) );

Dump to console. Note how the date is different in Montréal, as the new day has begun in Europe but not yet in America.

System.out.println( "dateTimeParis: " + dateTimeParis );
System.out.println( "dateTimeUTC: " + dateTimeUtc );
System.out.println( "dateTimeMontréal: " + dateTimeMontréal );

When run.

dateTimeParis: 2008-09-01T02:00:00.000+02:00
dateTimeUTC: 2008-09-01T00:00:00.000Z
dateTimeMontréal: 2008-08-31T20:00:00.000-04:00


The makers of Joda-Time have asked us to migrate to its replacement, the java.time framework as soon as is convenient. While Joda-Time continues to be actively supported, all future development will be done on the java.time classes and their extensions in the ThreeTen-Extra project.

The java-time framework is defined by JSR 310 and built into Java 8 and later. The java.time classes have been back-ported to Java 6 & 7 on the ThreeTen-Backport project and to Android in the ThreeTenABP project.

An Instant is a moment on the timeline in UTC with a resolution of nanoseconds. Its epoch is the first moment of 1970 in UTC.

Instant instant = Instant.ofEpochSecond( 1_220_227_200L );

Apply an offset-from-UTC ZoneOffset to get an OffsetDateTime.

Better yet, if known, apply a time zone ZoneId to get a ZonedDateTime.

ZoneId zoneId = ZoneId.of( "America/Montreal" );
ZonedDateTime zdt = ZonedDateTime.ofInstant( instant , zoneId );

Table of all date-time types in Java, both modern and legacy

Undefined Symbols error when integrating Apptentive iOS SDK via Cocoapods

We have found that adding the Apptentive cocoa pod to an existing Xcode project may potentially not include some of our required frameworks.

Check your linker flags:

Target > Build Settings > Other Linker Flags 

You should see -lApptentiveConnect listed as a linker flag:

... -ObjC -lApptentiveConnect ... 

You should also see our required Frameworks listed:

  • Accelerate
  • CoreData
  • CoreText
  • CoreGraphics
  • CoreTelephony
  • Foundation
  • QuartzCore
  • StoreKit
  • SystemConfiguration
  • UIKit

    -ObjC -lApptentiveConnect -framework Accelerate -framework CoreData -framework CoreGraphics -framework CoreText -framework Foundation -framework QuartzCore -framework SystemConfiguration -framework UIKit -framework CoreTelephony -framework StoreKit  

Oracle DB : java.sql.SQLException: Closed Connection

You have to validate the connection.

If you use Oracle it is likely that you use Oracle´s Universal Connection Pool. The following assumes that you do so.

The easiest way to validate the connection is to tell Oracle that the connection must be validated while borrowing it. This can be done with


But it works only if you hold the connection for a short period. If you borrow the connection for a longer time, it is likely that the connection gets broken while you hold it. In that case you have to validate the connection explicitly with

if (connection == null || !((ValidConnection) connection).isValid())

See the Oracle documentation for further details.

Confused about UPDLOCK, HOLDLOCK

UPDLOCK is used when you want to lock a row or rows during a select statement for a future update statement. The future update might be the very next statement in the transaction.

Other sessions can still see the data. They just cannot obtain locks that are incompatiable with the UPDLOCK and/or HOLDLOCK.

You use UPDLOCK when you wan to keep other sessions from changing the rows you have locked. It restricts their ability to update or delete locked rows.

You use HOLDLOCK when you want to keep other sessions from changing any of the data you are looking at. It restricts their ability to insert, update, or delete the rows you have locked. This allows you to run the query again and see the same results.

Align text in JLabel to the right

This can be done in two ways.

JLabel Horizontal Alignment

You can use the JLabel constructor:

JLabel(String text, int horizontalAlignment) 

To align to the right:

JLabel label = new JLabel("Telephone", SwingConstants.RIGHT);

JLabel also has setHorizontalAlignment:


This assumes the component takes up the whole width in the container.

Using Layout

A different approach is to use the layout to actually align the component to the right, whilst ensuring they do not take the whole width. Here is an example with BoxLayout:

    Box box = Box.createVerticalBox();
    JLabel label1 = new JLabel("test1, the beginning");

    JLabel label2 = new JLabel("test2, some more");

    JLabel label3 = new JLabel("test3");