...It's easy to use and is similar to Java's existing "AccessController.doPriviledged()" methods, so users who are familiar with the standard Java class will already be able to use the library. It is extremely customizable, so you can fine-tune exactly which permissions you wish to grant your untrusted code. It also includes many classes to to the hard work for you and has support for multi-threaded applications.
(I am also looking for people to maintain this project. If you are interested, please contact me at dudeprgm@gmail.com)