maven exec:java run class file within jar

Question

I have my code packaged into a jar

The jar is packaged ok.

jar -tfv target/test-1.0-SNAPSHOT.jar

com/
com/codevalid/
com/codevalid/App.class
log4j.xml
META-INF/maven/com.codevalid/test/pom.xml
META-INF/maven/com.codevalid/test/pom.properties

I can execute them when they are present as individual class files using exec:java

How to run class file within jar using maven exec:java?

Clavus

Sorry, How to run class file within jar using maven exec:java – Clavus

This might help. #42338357 – Kathe

Answer 1

Ok, this is what i finally ended up doing.
I built the jar using

mvn assembly:single

and used

java -jar ./target/App-1.0-SNAPSHOT-jar-with-dependencies.jar com.codevalid.App

I did see an alternative where i could have used

mvn exec:java -Dexec.mainClass="com.codevalid.App"

But i was not sure how pass the name of the jar as a classpath

Clavus

Answer 2

You can run a jar file using the exec:java goal by adding some arguments:

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>exec-maven-plugin</artifactId>
    <version>1.3.2</version>
    <configuration>
        <mainClass>org.example.Main</mainClass>
        <arguments>
            <argument>-jar</argument>
            <argument>target/myJar-1.0-SNAPSHOT.jar</argument>
        </arguments>
    </configuration>
</plugin>

If you have an executable jar and don't want to define the entry point, you need to set the executable and use the exec:exec goal:

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>exec-maven-plugin</artifactId>
    <version>1.3.2</version>
    <configuration>
        <executable>java</executable>
        <arguments>
            <argument>-jar</argument>
            <argument>target/myJar-1.0-SNAPSHOT.jar</argument>
        </arguments>
    </configuration>
</plugin>

Laforge

What if I want to pass some arguments to the main method of the org.example.Main class ? – Kathe

@Kathe I 'm haven't tested it but I think you can use <commandlineArgs> to pass arguments to the actual application – Laforge

Thanks for the suggestion, will check that. Anyway got an answer to the actual problem #42338357 – Kathe

Answer 3

You need to include your jar file as a dependency to the exec plugin, e.g. like this:

<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.2.1</version>
<executions>
  <execution>
    <phase>install</phase>
    <goals>
      <goal>java</goal>
    </goals>
    <configuration>
      <mainClass>com.codevalid.App</mainClass>
    </configuration>
  </execution>
</executions>
<dependencies>
  <dependency>
    <groupId>myGroup</groupId>
    <artifactId>test</artifactId>
    <version>1.0-SNAPSHOT</version>
  </dependency>
</dependencies>

You can skip the dependency declaration if the com.codevalid.App class is compiled as part of your current project.

Peursem

Hi, Thanks for the info, but this seems to work only if the jar in the repository. What i wanted to do is to test the jar, before i can install it in the repo. Is there any way where I can specify the location of this jar to maven exec:java – Clavus

@codevalid, @nwinkler's answer should be sufficient for your purposes because running mvn install on your dependent project in your local environment will put it in your local .m2 repository. – Sprite

Answer 4

You have to specify classpathScope and includePluginDependencies or includeProjectDependencies parameters to pickup jar files on the classpath.

Here is an example:

           <configuration>
                <executable>java</executable>
                <mainClass>com.google.jstestdriver.JsTestDriver</mainClass>
                <classpathScope>test</classpathScope>
                <includePluginDependencies>true</includePluginDependencies>
                <includeProjectDependencies>true</includeProjectDependencies>
                <commandlineArgs>--port 9876</commandlineArgs>
            </configuration>

Violet