TinyRadius is a small, fast and reliable Java Radius library capable of
sending and receiving Radius packets as specified by RFC 2865/2866. TinyRadius is not a fully-fledged Radius server, but helps you to implement Radius services in your application.
Extremely helpful, and I mean it! :)
It's a great start for a RADIUS server in Java!
It's excellent project for understand of Network programming concept .