Signals in Java

Revelations on Java Signal Handling is an important document to know how to catch signals in Java.

Stopping Java Threads listening on Sockets

You should read this link to for a recent discussion on how to interrupt threads that are listening on Socket's in Java:

http://www.javaworld.com/javaforums/showflat.php?Cat=2&Board=TheoryPractice&Number=382&page=0&view=collapsed&sb=7&o=&fpart=1