Animation.java

package animation;
import java.awt.*;

class MyFrame extends Frame implements Runnable
{
    int x,y,tx,ty;
    
    MyFrame()
    {
        x=100;
        y=100;
        tx=ty=1;
        
        Thread t=new Thread(this);
        t.start();
        
    }
    
    public void paint(Graphics g)
    {
        g.setColor(Color.RED);
        g.fillOval(x,y,50,50);
        
    }
    
    public void run()
    {
        while(true)
        {
            x+=tx;
            y+=ty;
            
            if(x<0 || x>450)
                tx=tx*-1;
            if(y<20 || y>350)
                ty=ty*-1;
            repaint();
            
            try{Thread.sleep(5);}catch(Exception e){}
        }
        
    }
    
}

public class Animation 
{
    public static void main(String[] args) 
    {
        MyFrame f=new MyFrame();
        f.setSize(500,400);
        f.setVisible(true);
        
    }    
}