To treat license headers in a unified and compliant way, this project uses the Mycila Licnse Maven Plugin http://code.mycila.com/license-maven-plugin/
In a (non-POM) project simply add:
<build>
<plugins>
<plugin>
<groupId>com.mycila</groupId>
<artifactId>license-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
to the project's POM.
Templates and settings defined in license are based on the entire project cloned.
Should modules have a different hierarchy, it may be necessary to adjust the configuration of header and headerDefinition from the parent POM.