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Do different types of Threads exist in JAVA?

Abhishek Dhar

Joined: Nov 07, 2006
Posts: 16
Hello friends i have some problem related to threads.......

I have once gone through a site there i read that there ar 2 types of threads.


It was a online samples of technical Q asked in interviews MNC like Google, Accenture, Cognizent etc

I have gone through various books like

1. A Programmer's Guide To Java Certification, 2nd Edition (Addison & Khalid).

2. Head First JAVA, 2 Edition (Kethy Sierra & Bert Bates).

In these books there is nothing written about the Types of Threads.
Do really the types of threads exist, if yes try to explan there definition.

Regards From ---- @bhishek Dh@r
Campbell Ritchie

Joined: Oct 13, 2005
Posts: 46375
Yes, there are two kinds of thread. Look through the Thread class in the API, and use ctrl-F then daemon.

A non-daemon thread (user thread) keeps running. If there are any non-daemon threads, the JVM keeps running too, until the last non-daemon thread "dies" (or finishes).

A daemon thread does not keep on running if all the non-daemon threads finish. So if you only have daemon threads still running, then the JVM will not keep running, and the daemon threads stop.

More poetically, from C Horstmann, G Cornell, Core Java 2 7/e vol II Advanced Features, Santa Clara: Sun Microsystems Press (Prentice-Hall) (2005) page 19:-
Daemon Threads

You can turn a thread into a daemon thread by calling


There is nothing demonic about such a thread. A daemon is simply a thread that has no other role in life than to serve others. Examples are timer threads that send regular "timer ticks" to other threads. When only daemon threads remain, the virtual machine exits. There is no point in keeping the program running if all remaining threads are daemons.
fred rosenberger
lowercase baba

Joined: Oct 02, 2003
Posts: 11955

closing as duplicate

There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors
I agree. Here's the link:
subject: Do different types of Threads exist in JAVA?
It's not a secret anymore!