Gabriel is a security framework for Java. By using access control lists and permissions, Gabriel enables components to check access to actions. On top of that Gabriel protects methods like EJB does but without the overhead. It distinguishes itself from other frameworks by the ease of use with a small API and by mapping method access to permissions instead of persons. This way the same permissions can be used to protect method access and to check which GUI elements to show based on user permissions.

Gabriel is open source and uses an Apache 2.0 license.
http://gabriel.codehaus.org/

Thanks to Bob and codehaus to make this possible.