This class demonstrates how to set Priority : Thread Priority « Thread « Java Tutorial

 * Copyright (c) 2004 David Flanagan.  All rights reserved.
 * This code is from the book Java Examples in a Nutshell, 3nd Edition.
 * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
 * You may study, use, and modify it for any non-commercial purpose,
 * including teaching and use in open-source projects.
 * You may distribute it non-commercially as long as you retain this notice.
 * For a commercial use license, or to purchase the book, 
 * please visit

 * This class demonstrates the use of threads. The main() method is the initial
 * method invoked by the interpreter. It defines and starts two more threads and
 * the three threads run at the same time. Note that this class extends Thread
 * and overrides its run() method. That method provides the body of one of the
 * threads started by the main() method
public class ThreadDemo extends Thread {
   * This method overrides the run() method of Thread. It provides the body for
   * this thread.
  public void run() {
    for (int i = 0; i < 5; i++)

   * This main method creates and starts two threads in addition to the initial
   * thread that the interpreter creates to invoke the main() method.
  public static void main(String[] args) {
    // Create the first thread: an instance of this class. Its body is
    // the run() method above
    ThreadDemo thread1 = new ThreadDemo();

    // Create the second thread by passing a Runnable object to the
    // Thread() construtor. The body of this thread is the run() method
    // of the anonymous Runnable object below.
    Thread thread2 = new Thread(new Runnable() {
      public void run() {
        for (int i = 0; i < 5; i++)

    // Set the priorities of these two threads, if any are specified
    if (args.length >= 1)
    if (args.length >= 2)

    // Start the two threads running

    // This main() method is run by the initial thread created by the
    // Java interpreter. Now that thread does some stuff, too.
    for (int i = 0; i < 5; i++)

    // We could wait for the threads to stop running with these lines
    // But they aren't necessary here, so we don't bother.
    // try {
    // thread1.join();
    // thread2.join();
    // } catch (InterruptedException e) {}

    // The Java VM exits only when the main() method returns, and when all
    // threads stop running (except for daemon threads--see setDaemon()).

  // ThreadLocal objects respresent a value accessed with get() and set().
  // But they maintain a different value for each thread. This object keeps
  // track of how many times each thread has called compute().
  static ThreadLocal numcalls = new ThreadLocal();

  /** This is the dummy method our threads all call */
  static synchronized void compute() {
    // Figure out how many times we've been called by the current thread
    Integer n = (Integer) numcalls.get();
    if (n == null)
      n = new Integer(1);
      n = new Integer(n.intValue() + 1);

    // Display the name of the thread, and the number of times called
    System.out.println(Thread.currentThread().getName() + ": " + n);

    // Do a long computation, simulating a "compute-bound" thread
    for (int i = 0, j = 0; i < 1000000; i++)
      j += i;

    // Alternatively, we can simulate a thread subject to network or I/O
    // delays by causing it to sleep for a random amount of time:
    try {
      // Stop running for a random number of milliseconds
      Thread.sleep((int) (Math.random() * 100 + 1));
    } catch (InterruptedException e) {

    // Each thread politely offers the other threads a chance to run.
    // This is important so that a compute-bound thread does not "starve"
    // other threads of equal priority.

10.3.Thread Priority
10.3.1.Change Thread Priority
10.3.2.Demonstrate thread priorities.
10.3.3.Minimum and Maximum Priority Threads
10.3.4.This class demonstrates how to set Priority