Maven license plugin allows you to update, remove, add license headers in one simple command line. You can also use it to check in the verify phase that your project files all have license headers.
Since first version and first announcement, there has been some improvements like:
- the support of multi module projects (to not scan sub modules when in the aggregator project
- the support of many more file types (of course, you can add your own)
- the ability to remove existing license headers
- the plugin is available from the Maven central repository
- and littles other bug fixes
You can get the licence plugin at http://code.google.com/p/maven-license-plugin/