Java Tutorial/Thread/ScheduledThreadPoolExecutor

Animation with ScheduledThreadPoolExecutor

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.geom.Ellipse2D;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import javax.swing.JComponent;
import javax.swing.JFrame;
public class BallRoom {
  public static void main(String[] a){
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setSize(200, 300);
    PaintSurface canvas = new PaintSurface();
    ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(3);
    executor.scheduleAtFixedRate(canvas, 0L, 100L, TimeUnit.MILLISECONDS);
    
    f.getContentPane().add(canvas);
    f.setVisible(true);
    
  }
}
class PaintSurface extends JComponent implements Runnable{
  int i = 0;
  public void run() {
    repaint();
  }
  public void paint(Graphics g) {
    Graphics2D g2 = (Graphics2D) g;
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    Shape ball = new Ellipse2D.Float(i++, i++, 5, 5);
    g2.setColor(Color.RED);
    g2.fill(ball);
  }
}

JDK1.5 provides a mechanism to create a pool a scheduled task

import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class Main{
  public static void main(String args[]) {
    ScheduledThreadPoolExecutor stpe = new ScheduledThreadPoolExecutor(5);
    
    stpe.scheduleAtFixedRate(new Job1(), 0, 5, TimeUnit.SECONDS);
    stpe.scheduleAtFixedRate(new Job2(), 1, 2, TimeUnit.SECONDS);
  }
}
class Job1 implements Runnable {
  public void run() {
    System.out.println("Job 1");
  }
}
class Job2 implements Runnable {
  public void run() {
      for(int i=0;i<99;i++){
        System.out.println(i);
      }
  }
}

Return a value from a thread.

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
public class Main {
  public static void main(String args[]) throws Exception{
    ExecutorService es = Executors.newFixedThreadPool(3);
    Future<Double> f = es.submit(new Task1());
    Future<Integer> f2 = es.submit(new Task2());
    System.out.println(f.get());
    System.out.println(f2.get());
    es.shutdown();
  }
}
class Task1 implements Callable<Double> {
  Task1() {
  }
  public Double call() {
    return 0.0;
  }
}
class Task2 implements Callable<Integer> {
  Task2() {
  }
  public Integer call() {
    return 1;
  }
}