Need help on a program on bouncing ball

[Gaurav Chandra]

I have a program on bouncing ball in applet but it does not have the main class, so it's running on blue j but not able to run it through DOS so if someone can help me out.

 import java.applet.Applet;
 import java.awt.Color;
 import java.awt.Graphics;
 /*<applet code= "Bounce.class" height=900 width=900> </applet>*/
 class Ball 
{
 int x,y,radius,dx,dy;
 Color BallColor;
 public Ball(int x,int y,int radius,int dx,int dy,Color bColor)
 {
 this.x=x; this.y=y;
 this.radius=radius;
 this.dx=dx;
 this.dy=dy; 
BallColor=bColor;
 }
 }
 public class Bounce extends Applet implements Runnable
{
 Ball redBall;
 public void init()
 {
redBall=new Ball(250,80,50,2,4,Color.red);
 Thread t=new Thread(this);
 t.start();
 }
 public void paint(Graphics g)
 { 
g.setColor(redBall.BallColor); 
setBackground(Color.pink);
 //g.setcolor(redBall.BallColor);
 g.fillOval(redBall.x, redBall.y, redBall.radius,redBall.radius);
 g.drawLine(150,400,50,500);
 g.drawLine(150,400,450,400);
 g.drawLine(50,500,350,500);
 g.drawLine(450,400,350,500);
 g.drawRect(50,500,20,100);
 g.drawRect(330,500,20,100);
 g.drawLine(450,400,450,500);
 g.drawLine(430,500,450,500); 
g.drawLine(430,500,430,420);
 }
public void run()
 { 
while(true)
 {
 try
 {
 displacementOperation(redBall);
 Thread.sleep(20);
 repaint();
 } 
catch(Exception e){}
 } 
}
 public void displacementOperation(Ball ball)
 {
 if(ball.y >= 400 || ball.y <= 0) { ball.dy=-ball.dy; } ball.y=ball.y+ball.dy;
 }
}

Thanks in advance

[Tony Docherty]

This is an Applet so you generally run it via a browser.
What do you mean by not being able to run it through DOS? Do you mean you want to launch it from the command line or do you mean you want to run it as a standalone program or something else altogether? Please explain exactly what you are trying to do.