苦恼的问题,郁闷很多天！！

import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.MediaTracker;
import javax.swing.*;public class InfoPanel extends JPanel
{
    private Image img = Toolkit.getDefaultToolkit().getImage(
                InfoPanel.class.getResource("DDG51.gif"));
    private int count = 0;    public InfoPanel()
    {
MediaTracker tracker=new MediaTracker(this);
tracker.addImage(img,0);
try
{
tracker.waitForID(0);
}
catch(InterruptedException e)
{
e.printStackTrace();
}
    }    public void paint(Graphics g){
        super.paint(g);
        g.drawImage(img,0,0,this.getWidth(),this.getHeight(),this);
        count ++;
        System.out.println(count);
    }    public static void main(String[] args){
        JFrame f = new JFrame();
        f.addWindowListener(new WindowAdapter(){
            public void windowClosing(WindowEvent e){
                System.exit(0);
            }
        });
        f.setSize(400,200);
        InfoPanel info = new InfoPanel();
        f.getContentPane().add(info);
        f.setVisible(true);
    }
}