Exec goal

You can formally specify all the relevant execution information in the plugin configuration. Depending on your cases, you can also specify some or all information using system properties.

Command line

Using the system properties you would just execute it like the following example.

> mvn exec:exec -Dexec.executable="maven" [-Dexec.workingdir="/tmp"] -Dexec.args="-X myproject:dist"

Exec Plugin Configuration

Add configuration similar to the following to your POM:

<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.1-beta-2</version>
        <executions>
          <execution>
            ...
            <goals>
              <goal>exec</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <executable>maven</executable>
          <!-- optional -->
          <workingDirectory>/tmp</workingDirectory>
          <arguments>
            <argument>-X</argument>
            <argument>myproject:dist</argument>
            ...
          </arguments>
        </configuration>
      </plugin>
    </plugins>
  </build>
   ...
</project>

Java goal

This mojo helps you run a Java program within the same VM as maven.

Differences compared to plain command line

The mojo goes to great length to try to mimic the way the VM works, but there are some small subttle differences. Today all differences come from the way the mojo deals with thread management .

command line Java Mojo
the VM exits as soon as the only
remaining threads are daemon threads		 By default daemon threads are joined
and interrupted once all known non
daemon threads have quitted. The join
timeout is customisable
The user might wish to further cleanup
cleanup by stopping the unresponsive
threads.
The user can disable the full extra
thread management (interrupt/join/[stop])

Read the java for more information on how to configure this behavior.

If you find out that these differences are unacceptable for your case, you may need to use the exec mojo to wrap your java executable.

Command line

If you want to execute Java programs in the same VM, you can either use the command line version

> mvn exec:java -Dexec.mainClass="com.example.Main" [-Dexec.args="argument1"] ...

Java Plugin Configuration

either configure the plugin in your pom:

<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.1-beta-2</version>
        <executions>
          <execution>
            ...
            <goals>
              <goal>java</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <mainClass>com.example.Main</mainClass>
          <arguments>
            <argument>argument1</argument>
            ...
          </arguments>
          <systemProperties>
            <systemProperty>
              <key>myproperty</key>
              <value>myvalue</value>
            </systemProperty>
            ...
        </configuration>
      </plugin>
    </plugins>
  </build>
   ...
</project>

Note: the java goal doesn't spawn a new process. Any VM specific option that you want to pass to the executed class must be passed to the maven VM using the MAVEN_OPTS environment variable. E.g.

MAVEN_OPTS=-Xmx1024m

Otherwise consider using the exec goal.