Shaj
Shaj (Simple Host Authentication for Java) is a simple library that allows your Java app to verify users with the underlying operating system. Shaj also allows you to check group membership. Shaj is not a competitor for full featured authentication API's but rather a complimentary way to piggyback on system accounts on any platforms.
Shaj is used in FishEye for local account authentication, hence it is in use on most flavours of Windows and *NIX.
Shaj currently supports Windows and Unix (PAM), and comes with pre-compiled JNI libraries for win32, Linux, Mac OS-X and Solaris. Shaj should work on Java 1.2+ JVM's. Shaj is written in C and Java.
Shaj is licensed under the Apache 2.0 License.
If you need any help with Shaj, visit the forums.
Download Shaj, Browse the Source with FishEye
Overview