What's the difference between user thread and daemon thread in java? [duplicate]

Question

Possible Duplicate:
What is Daemon thread in java
When are daemon threads useful?

I am confused with the difference between user threads and daemon threads in Java.

Can you tell me:

1. What's the difference between user threads and daemon threads in Java?
2. In which situation daemon thread will be used? Can you give me some examples?

Answer 1

a JVM will exit once the last non-jvm thread terminates. this means that if any of the threads you create is still running, the jvm will not shutdown. daemon threads are threads that do not prevent the JVM from shutting down. normally you'd use them for some background tasks which you dont want keeping your application up if the user requested it to shut down.

also, your question was already asked (and answered) here - What is Daemon thread in Java?

some common (from personal experience) use cases for daemon threads might include

• background threads that poll remote systems for status changes
• background work threads (things like sending out email notifications, snmp, whatever)
• custom timer threads meant to perform scheduled maintainance

Answer 2

2nd Question :

Daemon threads get automatically terminated when all normal threads have been terminated.

You can use daemon threads to do some housekeeping or cleaning in your application. Daemon threads are used for background supporting tasks and are only needed while normal threads are executing. GC thread is a daemon thread.