In this segment of tutorial we will learn about the Daemon Thread.Then We will create an example and make the use of Daemon thread.

• Daemon thread is the supporting thread.
• It runs in the background.
• Daemon thread gets teminated if no non daemons threads are running.
• Any threads can be set as daemon thread.

Java Daemon Thread Example

public class deamon extends Thread {
	public deamon(String s) {
		super(s);
	}

	@Override
	public void run() {
		System.out.println("entering run()");
		try {
			System.out.println("in run() - currentThread()="
					+ Thread.currentThread());
			for (int x = 1; x <= 3; x++) {

				System.out.println(x + "   this is daemon thread "
						+ Thread.currentThread().isDaemon());
				try {
					Thread.sleep(300);
				} catch (Exception e) {
					e.printStackTrace();
				}
				System.out.println("thread woke up again");
			}
		} catch (Exception e) {
			System.out.println(e.getMessage());
		}
	}

	public static void main(String[] args) {
		deamon d1 = new deamon("1");
		d1.setDaemon(true);
		deamon d2 = new deamon("2");
		deamon d3 = new deamon("3");
		d1.start();
		d2.start();
		d3.start();
	}
}

Output :

entering run() entering run() in run() - currentThread()=Thread[1,5,main] in run() - currentThread()=Thread[3,5,main] 1 this is daemon thread false 1 this is daemon thread true entering run() in run() - currentThread()=Thread[2,5,main] 1 this is daemon thread false thread woke up again 2 this is daemon thread false thread woke up again 2 this is daemon thread true thread woke up again 2 this is daemon thread false thread woke up again 3 this is daemon thread false thread woke up again 3 this is daemon thread true thread woke up again 3 this is daemon thread false thread woke up again thread woke up again thread woke up again

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