This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
The JVM will exit when all the threads that remain running are daemon threads. Therefore, if you want to create a Thread that runs as a sort of background task, and you don't want the program to continue running if your main thread terminates but the background task remains, then you should make that background thread a daemon thread.