A look into the changelog shows three issues of which only METAGEN-45 is worth mentioning. Several people reported problems with metamodel classes not getting compiled, especially when the annotation processor was used in conjunction with the -s option (which specifies where to place generated source files). This is resolved by METAGEN-45.
I also would like to follow up on the question on how to best integrate the processor into maven build. As always there are more than one way to skin a cat and here is my preferred version:
... <plugins> <plugin> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>1.6</source> <target>1.6</target> <compilerArgument>-proc:none</compilerArgument> </configuration> </plugin> <plugin> <groupId>org.bsc.maven</groupId> <artifactId>maven-processor-plugin</artifactId> <version>1.3.7</version> <executions> <execution> <id>process</id> <goals> <goal>process</goal> </goals> <phase>process-sources</phase> </execution> </executions> <dependencies> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-jpamodelgen</artifactId> <version>1.1.0.Final</version> <scope>compile</scope> </dependency> </dependencies> </plugin> ...
The benefits of this version are that there is no need for the build-helper plugin and, more importantly, the processor is defined as a plugin dependency of the maven-processor-plugin instead of a direct project dependency. You find this and other setup versions in the online documentation of the Hibernate Metamodel Generator.
As always, feedback is always welcome. If you find a bug make sure to report it in METAGEN.