Issue in plugin dependency jar in multi-module pom

Question

There is a top level pom.xml which calls two sub modules as below:

<modules>
        <module>module1</module>
        <module>module2</module>        
</modules>

Where module2 is dependent on module1

The xjc plugin configuration in module1 pom.xml is as below:

  <build>
    <plugins>
            <plugin>
                <groupId>com.sun.tools.xjc.maven2</groupId>
                <artifactId>maven-jaxb-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <strict>false</strict>
                    <extension>true</extension>
                    <verbose>true</verbose>
                </configuration>               
            </plugin>
    </plugins>
  </build>

The xjc configuration in module2's pom.xml is as below:

      <build>
        <plugins>
               <plugin>
                    <groupId>com.sun.tools.xjc.maven2</groupId>
                    <artifactId>maven-jaxb-plugin</artifactId>
                <dependencies>
                   <dependency>
                      <groupId>com.mycompany.module1</groupId>
                      <artifactId>module1</artifactId>
                      <version>1.0</version>
                      <scope>runtime</scope>
                   </dependency>
                </dependencies>
                    <executions>
                        <execution>
                            <goals>
                                <goal>generate</goal>
                            </goals>
                        </execution>
                    </executions>
                    <configuration>
                <includeSchemas>
                  <includeSchema>schema.xsd</includeSchema>
                </includeSchemas>
                <includeBindings>
                  <includeBinding>bindings.xjb</includeBinding>
                </includeBindings>      
                        <strict>false</strict>
                        <extension>true</extension>
                        <verbose>true</verbose>
                        <args>-Xpdm</args>                                      
                    </configuration>                 
                </plugin>
        </plugins>
  </build>

Now when I run mvn from top level directory then module2 build fails, I get the below error:

[INFO] unrecognized parameter -Xpdm
[INFO] ------------------------------------------------------------------------
[INFO] Trace
unrecognized parameter -Xpdm
        at com.sun.tools.xjc.XJC2Task._doXJC(XJC2Task.java:446)
        at com.sun.tools.xjc.XJC2Task.doXJC(XJC2Task.java:434)

The reason for this error was because module1 dependency was not used while XJC plugin execution during module2 build.

My question: why module2's xjc plugin configuration did not come into effect?

When I run mvn in module2 directory it works fine but from top level directory it fails.

Any help, what I am missing at?

Answer 1

It is a limitation/bug of Maven 2.x, where all executions of a plugin in a multi-module project has the same classpath. It has been fixed in Maven 3 (since one of the alphas).