farooq,
I am giving a reference Baldwin's
Java Tutorial
Daemon Threads According to
Java Primer Plus, if you set a thread as a daemon thread using setDaemon() method, you are specifying that the thread belongs to the system and not to the process that spawned it.Daemon threads are useful if you want a thread to run in the background for extended periods of time.
According to Deitel and Deitel,
Java, How to Program,
"A daemon thread is a thread that runs for the benefit of other threads." Daemon threads run in the background and do not prevent a program from terminating. For example, the garbage collector is a daemon thread.
A program can include a mixture of daemon and non-daemon threads. The Java virtual machine will exit when only daemon threads remain in a program.
regds
maha anna