[java] How to build jars from IntelliJ properly?

I have a project that contains a single module, and some dependencies. I'd like to create a jar, in a separate directory, that contains the compiled module. In addition, I'd like to have the dependencies present beside my module.

No matter how I twist IntelliJ's "build jar" process, the output of my module appears empty (besides a META-INF file).

This is still an issue in 2017, I hope it will help somebody out there! I found 2 possibilities to create working jar-s under IntelliJ 2017.2

1. Creating artifact from IntelliJ:

• Go to project structure:

• Create a new artifact:

• Select the main class, and be sure to change the manifest folder:

You have to change manifest directory:

<project folder>\src\main\java 

replace "java" with "resources"

<project folder>\src\main\resources

This is how it should look like:

• Then you choose the dependencies what you want to be packed IN your jar, or NEAR your jar file

• To build your artifact go to build artifacts and choose "rebuild". It will create an "out" folder with your jar file and its dependencies.

2. Using maven-assembly-plugin

Add build section to the pom file

    <build>
        <plugins>
            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <configuration>
                    <finalName>ServiceCreate</finalName>
                    <appendAssemblyId>false</appendAssemblyId>
                    <archive>
                        <manifest>
                            <mainClass>com.svt.optimoo.App</mainClass>
                        </manifest>
                    </archive>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

• Create a new run/debug configuration:

• Choose application:

• Fill in the form
• Add the "assembly:single" maven goal after build to be executed last

• Save it, then run

This procedure will create the jar file under the "target" folder

With Maven you can use this plugin:

 <build>
    <plugins>

        <plugin>
            <artifactId>maven-assembly-plugin</artifactId>
            <configuration>
                <archive>
                    <manifest>
                        <mainClass>[path you class main]</mainClass>
                    </manifest>
                </archive>
                <descriptorRefs>
                    <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
            </configuration>
            <executions>
                <execution>
                    <id>make-assembly</id>
                    <phase>package</phase> 
                    <goals>
                        <goal>single</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

If you are using third party libraries with your project or if you have problems with creating MANIFEST.MF file properly, there can be conflicts when running JAR files generated using

File > Project Structure > Artifacts > '+' > JAR > From modules with dependencies > .....

method mentioned above.

Instead I suggest you to create an empty JAR and add all other elements to the output root manually. A wonderful blog article for this method can be found here: http://karthicraghupathi.com/2016/07/10/creating-an-executable-jar-in-intellij-idea/ I tried the steps mentioned there and everything worked fine for me!

Here are 2 examples with maven project, step by step:

Method 1: Build jar with maven and pom.xml

1. File, new, project, maven
2. create a package , create a java program inside that package

3. at pom.xml, add maven-jar-plugin.

       <plugin>
           <!-- Build an executable JAR -->
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-jar-plugin</artifactId>
           <version>3.1.0</version>
           <configuration>
               <archive>
                   <manifest>
                       <addClasspath>true</addClasspath>
                       <classpathPrefix>lib/</classpathPrefix>
                       <mainClass>somePackage.sample</mainClass>
                   </manifest>
               </archive>
           </configuration>
       </plugin>
   

screen capture: 4. open maven project box by click on the search icon and type maven,

5. click on clean, then click on install

6. your jar file will show up inside the target folder

7. test your jar using java -jar

Method 2: Build jar with maven without pom.xml change

1. File, new, project, maven
2. create a package , create a java program inside that package (same as above)
3. File -> Project Structure -> Project Settings -> Artifacts -> Click green plus sign -> Jar -> From modules with dependencies

Very important!

The MANIFEST.MF needs to be in your resources folder and the Main.Class needs to refer to {package}-{class-name-that-contains-main-class}

4. then click build on menu , build artifacts, build

5. find the jar in the out folder

6. run it :)

It is probably little bit late, but I managed to solve it this way -> open with winrar and delete ECLIPSEF.RSA and ECLIPSEF.SF in META-INF folder, moreover put "Main-class: main_class_name" (without ".class") in MANIFEST.MF. Make sure that you pressed "Enter" twice after the last line, otherwise it won't work.

Some of the other answers are useless because as soon as you re-import the IntelliJ IDEA project from the maven project, all changes will be lost.

The building of the jar needs to be triggered by a run/debug configuration, not by the project settings.

Jetbrains has a nice description of how you can accomplish this here:

https://www.jetbrains.com/help/idea/maven.html

Scroll down to the section called "Configuring triggers for Maven goals".

(The only disadvantage of their description is that their screenshots are in the default black-on-white color scheme instead of the super-awesome darcula theme. Ugh!)

So, basically, what you do is that you open the "Maven Projects" panel, you find the project of interest, (in your case, the project that builds your jar,) underneath it you find the maven goal that you want to execute, (usually the "package" goal creates jars,) you open up the context menu on it, (right-click on a Windows machine,) and there will be an "Execute before Run/Debug..." option that you can select and it will take you by the hand from there. Really easy.

Idea 8.1.3

Jar is ok, since there is compiled output in 'output' directory (project/out/production//)

I guess, you have to run 'make' before building jar

for dependencies just check "show library" and choose what you want.

In case you are trying to build a jar with kotlin you need to create a src/main/java folder and use this folder as a location for the META-INF folder.

Use Gradle to build your project, then the jar is within the build file. Here is a Stack Overflow link on how to build .jar files with Gradle.

Java project with Gradle and building jar file in Intellij IDEA - how to?

You might want to take a look at Maven (http://maven.apache.org). You can use it either as the main build process for your application, or just to perform certain tasks through the Edit Configurations dialog. The process of creating a JAR of a module within Maven is fairly trivial, if you want it to include all the dependencies in a self-executable JAR that is trivial as well.

If you've never used Maven before then you want to read Better Builds With Maven.

As the people above says, but I have to note one point. You have to check the checkbox:

Include in project build

When i use these solution this error coming:

java -jar xxxxx.jar

no main manifest attribute, in xxxxx.jar

and solution is:

You have to change manifest directory:

<project folder>\src\main\java 

change java to resources

<project folder>\src\main\resources

Here is the official answer of IntelliJ IDEA 2018.3 Help. I tried and It worked.

To build a JAR file from a module;

1. On the main menu, choose Build | Build Artifact.

2. From the drop-down list, select the desired artifact of the type JAR. The list shows all the artifacts configured for the current project. To have all the configured artifacts built, choose the Build all artifacts option.

If you are working on spring/mvn project you can use this command:

mvn package -DskipTests

The jar file will be saved on target directoy.

My problem was this: I used Intellij IDEA (tried different versions) + Gradle. When I compiled the project and builded artifacf jar, as indicated in the above responses, I received an error - "no main manifest attrubute ..."

This solution worked for me (special thanks to Thilina Ashen Gamage (see above) for tip):

Excerpt - if you use external libraries and build a project through Project Settings - Artifacts - Add (+) - Jar - From modules with dependencies, then probably because of a program bug the META-INF folder with MANIFEST_MF file not including to jar. To avoid it create EMPTY jar file.

Project Settings - Artifacts - Add (+) - Jar - EMPTY JAR. META-INF folder will added to resources folder. Then select your main class. You will see following jar structure: Note the presence of a folder META-INF Then you can build your project and build artifacts. This solution worked for javaFX applications too.

For those that benefit from images as I do:

File -> Project Structure

I recently had this problem and think these steps are easy to follow if any prior solution or link is missing detail.

How to create a .jar using IntelliJ IDEA 14.1.5:

1. File > Save All.
2. Run driver or class with main method.
3. File > Project Structure.
4. Select Tab "Artifacts".
5. Click green plus button near top of window.
6. Select JAR from Add drop down menu. Select "From modules with dependencies"
7. Select main class.
8. The radio button should be selecting "extract to the target JAR." Press OK.
9. Check the box "Build on make"
10. Press apply and OK.
11. From the main menu, select the build dropdown.
12. Select the option build artifacts.

Ant and Maven are widely used. I prefer Ant, I feel it's more lightweight and you the developer are more in control. Some would suggest that's its downside :-)

I was trying to build a jar from a multi-module Kotlin app and was getting the notorious 'no main manifest attribute' error. Creating the manifest directory in src/main/resources didn't work either.

Instead, it works when creating it in src directly: src/META-INF/MANIFEST.MF.

In case you are reading this answer because you are facing "resource file not found" error, try this:

1. File -> Project Structure -> Artiface -> New, type is Other.
2. Give it a nice name, and in the Output Layout, press Create Archive to create a new jar, and again, give it a nice name ;)
3. Click on the jar you just added, add your compiled module output in the jar.
4. Click on the jar again, in the lower pane, select your project path and add Manifest File then set correct Main Class and Class Path.
5. Click Add Library Files, and select libraries you need (you can use Ctrl+A to select all).
6. Build -> Build Artifact -> Clean & Build and see if the error is gone.