import javax.swing.JFrame;
import java.awt.*;

public class UsageThread {
  public UsageThread() {}

  public static void main(String[] args) {

    JFrame frame = new JFrame("Slot Machine");

    ball game1 = new ball(250, "1");
    ball game2 = new ball(50, "2");
    ball game3 = new ball(50, "3");

    frame.setSize(500, 500);
    frame.setLocation(50, 50);
    frame.add(game1);
    frame.add(game2);
    frame.add(game3);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(3);
    game1.start();
    game2.start();
    game3.start();
    game1.stop();
    game2.stop();
    game3.stop();

  }
}

------------------------------------------

import java.awt.Color;
import java.awt.Graphics2D;
import java.io.PrintStream;

public class ball extends javax.swing.JPanel implements Runnable
{
  public int x;
  public int y = 0;
  public String b;
  Thread t;

  public ball(int a, String c) { x = a;

    b = c;
    System.out.println("Creating " + c);
  }

  public void paint(java.awt.Graphics g) {
    super.paint(g);

    Graphics2D g2d = (Graphics2D)g;
    Graphics2D g3d = (Graphics2D)g;
    Graphics2D g4d = (Graphics2D)g;



    int n1 = (int)(Math.random()*3);
    int n2 = (int)(Math.random()*3);
    int n3 = (int)(Math.random()*3);

    switch(n1){
    case 0:
    	g2d.setColor(Color.blue);
    	g2d.fillOval(10, 10, 30, 30);
    	break;
    case 1:
    	g2d.setColor(Color.green);
    	g2d.fillOval(10, 10, 30, 30);
    	break;
    case 2:
    	g2d.setColor(Color.red);
    	g2d.fillOval(10, 10, 30, 30);
    	break;
    }
    switch(n2){
    case 0:
    	g3d.setColor(Color.blue);
    	g3d.fillOval(50, 10, 30, 30);
    	break;
    case 1:
    	g3d.setColor(Color.green);
    	g3d.fillOval(50, 10, 30, 30);
    	break;
    case 2:
    	g3d.setColor(Color.red);
    	g3d.fillOval(50, 10, 30, 30);
    	break;
    }
    switch(n3){
    case 0:
    	g4d.setColor(Color.blue);
    	g4d.fillOval(90, 10, 30, 30);

    case 1:
    	g4d.setColor(Color.green);
    	g4d.fillOval(90, 10, 30, 30);

    case 2:
    	g4d.setColor(Color.red);
    	g4d.fillOval(90, 10, 30, 30);
    }



  }




  public void run()
  {

        y += 1;

        if (y < 450) {
          y += 30;
          repaint();
        } else {
          y = 30;
          repaint();
        }
        System.out.println(x);
        repaint();


  }

  public void start() {
    if (t == null) {
      t = new Thread(this);
      t.start();
    }
  }
  public void stop() {
        if (t == null) {
          t = new Thread(this);
          t.stop();
        }
      }
}