Thread Priority not working properly

[Kashinath Roy]

But Why low is executing count more then High thread despite low priroty is low

Code:

class clicker implements Runnable {
	  int click = 0;
	  Thread t;
	  private volatile boolean running = true;
	  public clicker(int p) {
	    t = new Thread(this);
	    t.setPriority(p);
	  }

	  public void run() {
	    while (running) {
	      click++;
	    }
	  }

	  public void stop() {
	    running = false;
	  }

	  public void start() {
	    t.start();
	  }
	}


class HiLoPri {
	  public static void main(String args[]) {
	    Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
	    clicker hi = new clicker(Thread.NORM_PRIORITY+2);
	    clicker lo = new clicker(Thread.NORM_PRIORITY-2);
	    hi.start();
	    lo.start();
	    try {
	      Thread.sleep(10000);
	    } catch (InterruptedException e) {
	      System.out.println("Main thread interrupted.");
	    }
	    lo.stop();
	    hi.stop();
	    try {
	      hi.t.join();
	      lo.t.join();
	    } catch (InterruptedException e) {
	      System.out.println("InterruptedException caught");
	    }
	    System.out.println("Low-priority thread: " + lo.click);
	    System.out.println("High-priori  thread: " + hi.click);
	  }
	}

Eclipsc IDE OUTPUT

Low-priority thread: 382730681
High-priori thread: 22847397

[Harsha Smith]

Thread priorities don't often produce desired results. Although you can assign higher priority to the tasks you want to run before others, this may not work as you expect and also I think it depends on the OS

[Henry Wong]

Computers can do a lot in 10 seconds. Are you sure that the integers are not overflowing?

Henry

[Nomaan Butt]

one can't be sure of the outcome when using threads, a lot depends on the OS and JVM. By the way in my system your program is giving expected results see below,

Low-priority thread: 1580488402
High-priori thread: 1658625472

try changing the priority values, which jvm you are using?