Assuming you have configured the Maven JMod Plugin accordingly to the usage page like the following:
<project>
  [...]
  <build>
    [...]
    <plugins>
      [...]
      <plugin>
        <artifactId>maven-jmod-plugin</artifactId>
        <version>3.0.0-alpha-1</version>
        <extensions>true</extensions>
        <configuration>
          <!-- configuration elements goes here -->
        </configuration>
        <executions>
          <execution>
            <id>list</id>
            <goals>
              <goal>list</goal>
            </goals>
            <phase>verify</phase>
          </execution>
        </executions>
      </plugin>        
      </plugin>
   [...]
</project>You can run via:
mvn clean verify
During the above call of Maven the jmod files will be generated and by the list goal you will get an output like the following (using toolchains):
[INFO] --- maven-jmod-plugin:3.0.0-alpha-1:list (list) @ first-jmod --- [INFO] Toolchain in maven-jmod-plugin: jmod [ /../jdk1.9.0_ea+181.jdk/Contents/Home/bin/jmod ] [INFO] The following files are contained in the module file /../maven-single-jmod-example/target/jmods/first-jmod.jmod [INFO] classes/module-info.class [INFO] classes/com/corporate/project/Main.class [INFO] conf/config.1 [INFO] conf/config.2 [INFO] conf/sub-configuration/config.sub [INFO] include/first.h [INFO] legal/first.md [INFO] bin/first.cmd [INFO] bin/first.sh [INFO] bin/test.sh [INFO] lib/native-lib.so [INFO]