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import java.awt.*;public class MyBall {    public static void main(String args[]){    	Frame w=new Frame();    	w.setSize(300, 400);    	MyPanel mp=new MyPanel();    	w.add(mp);    	Thread t=new Thread(mp);       	t.start();    	w.setVisible(true);    }}class MyPanel extends Panel implements Runnable{	int x=30;	int y=30;	public void paint(Graphics g){		g.fillOval(x, y, 20, 20);	}	public void run(){			while(true){						y++;				if(y>400){					y=0;				}				try{					Thread.sleep(30);						}catch(Exception e){}				repaint();			}			}			}

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