JPA Hibernate Metamodel generation through maven

Question

I followed the JPA modelgen guide and i was able to generate the canonical metamodel which i need. With this pom set up:

Answer 1

I'm also using JPA Metamodel generator and I don't have the problems you describe, maybe my configuration can help, I see some differences, the first one is maven-processor-plugin

<plugin>
  <groupId>org.bsc.maven</groupId>
  <artifactId>maven-processor-plugin</artifactId>
  <version>2.1.0</version>
  <executions>
    <execution>
      <id>process</id>
      <goals>
        <goal>process</goal>
      </goals>
      <phase>generate-sources</phase>
      <configuration>
        <processors>
          <processor>org.hibernate.jpamodelgen.JPAMetaModelEntityProcessor</processor>
        </processors>
      </configuration>
    </execution>
  </executions>
  <dependencies>
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-jpamodelgen</artifactId>
      <!--version>1.2.0.Final</version-->
      <version>4.3.4.Final</version>
    </dependency>
  </dependencies>
</plugin>

As you can see I had to add hibernate-jpamodelgen as dependency and the processor attribute.

I am not sure if build-helper-maven-plugin is necessary to add the directory of generated sources to your source path. I am not using it and it works for me but maybe it's because I am using the default output path for generated sources.