// tasks/SimpleDaemons.java
// (c)2016 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
// Daemon threads don't prevent the program from ending
import java.util.concurrent.*;

public class SimpleDaemons implements Runnable {
  @Override
  public void run() {
    try {
      while(true) {
        TimeUnit.MILLISECONDS.sleep(100);
        System.out.println(
          Thread.currentThread() + " " + this);
      }
    } catch(InterruptedException e) {
      System.out.println("sleep() interrupted");
    }
  }
  public static void
  main(String[] args) throws Exception {
    for(int i = 0; i < 10; i++) {
      Thread daemon = new Thread(new SimpleDaemons());
      daemon.setDaemon(true); // Must call before start()
      daemon.start();
    }
    System.out.println("All daemons started");
    TimeUnit.MILLISECONDS.sleep(175);
  }
}
/* Output:
All daemons started
Thread[Thread-6,5,main] SimpleDaemons@b87187
Thread[Thread-4,5,main] SimpleDaemons@1fb28c1
Thread[Thread-8,5,main] SimpleDaemons@8ebcf
Thread[Thread-7,5,main] SimpleDaemons@54761d
Thread[Thread-9,5,main] SimpleDaemons@156afef
Thread[Thread-0,5,main] SimpleDaemons@1320c4d
Thread[Thread-3,5,main] SimpleDaemons@4683f2
Thread[Thread-2,5,main] SimpleDaemons@4f80f2
Thread[Thread-5,5,main] SimpleDaemons@29c11d
Thread[Thread-1,5,main] SimpleDaemons@9df74c
*/