Forking Java using the Exec Maven Plugin, without using the `exec` goal

Question

exec:exec execute programs and Java programs in a separate process.
exec:java execute Java programs in the same VM.

I want to fork a java program. I've already got it working in exec:java but that doesn't fork. So the obvious move is to change the goal to exec. Problem is, the syntax for exec is pretty different from the syntax of java. It doesn't have tags like includeProjectDependencies, includePluginDependencies, etc. Is there a plugin I can use that is like #1 in the sense that it forks, but has a convenient syntax like #2? IMO, #2 should just have a <fork>true</fork> configuration.

You could always modify the Exec Maven plugin to fork the Java process but keep includeProjectDependencies and includePluginDependencies http://svn.codehaus.org/mojo/tags/exec-maven-plugin-1.2.1/src/main/java/org/codehaus/mojo/exec/ExecMojo.java — , Jun 10 '13 at 19:39

score 4 · Answer 1 · answered Apr 25 '18 at 16:33

It's also possible to spawn a Java process from Maven with the maven-antrun-plugin. This plugin exports several classpaths covering the compile/runtime/test scopes, as well as the plugin dependencies.

Executing a class in a separate process with the compile and plugin dependencies would thus look like this:

<plugin>
  <artifactId>maven-antrun-plugin</artifactId>
  <goals>
    <goal>run</goal>
  </goals>
  <configuration>
    <target>
      <java classname="com.example.MainClass" fork="true">
        <classpath>
          <path refid="maven.compile.classpath"/>
          <path refid="maven.plugin.classpath"/>
        </classpath>
      </java>
    </target>
  </configuration>
</plugin>

This is executed with mvn antrun:run instead of exec:exec.

score 3 · Answer 2 · answered Jun 12 '13 at 10:13

3

I think you can stick to exec:exec, using that kind of configuration if you want to give the project classpath to the Java process you use:

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>exec-maven-plugin</artifactId>
    <configuration>
        <executable>java</executable>
        <longClasspath>true</longClasspath>
        <arguments>
            <argument>-XX:MaxPermSize=128M</argument>
            <argument>-Xmx1024M</argument>
            <argument>-Xdebug</argument>
            <argument>-Xrunjdwp:transport=dt_socket,address=8888,server=y,suspend=n</argument>
            <argument>-classpath</argument>
            <classpath/>
        </arguments>
    </configuration>
</plugin>

See also the plugin Usage page

answered Jun 12 '13 at 10:13

Tome

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Where are you configuring `includeProjectDependencies` and `includePluginDependencies` here? – Daniel Kaplan Jun 12 '13 at 17:11
Project dependencies are added through argument. I don't think you can add plugin dependencies though, but is it really an issue? – Tome Jun 13 '13 at 09:49
4

For me it is. I'm running a deployer. The deployer has no business being on the actual app's classpath. – Daniel Kaplan Jun 13 '13 at 17:13
Not work for me, I ended up with IntelliJ Run/Debug Configratuion > Runner > VM Options, specify vm options for maven in the first place. – Jerry Chin Sep 12 '19 at 08:26
Just add the class to run as the last argument. – Rusi Popov Nov 03 '21 at 07:27

Forking Java using the Exec Maven Plugin, without using the `exec` goal

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