To manage the updating and adding of license headers in java as well as XML files, the mvn-license-plugin was included. Find detailed information under http://code.google.com/p/maven-license-plugin/ .
To add/update all headers in all files, simply execute the following command on the main project:
Note that this command adapts all XML as well (even the test-ones) but excludes the pom.xml-files. Therefore, these files must be adapted in an additional step.