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.x         


        

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

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>

Answer 3

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>

Answer 4

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.