<applet code="a_duke_1.class" width="480" height="360">...</applet>

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class a_duke_1 extends    Applet
                      implements MouseListener
{ 
   private Image immagine;
   private int   x, y;

   public void init()
   {
      x=getSize().width/2;
      y=getSize().height/2; 
      immagine=getImage(getCodeBase(), "duke.jpg");
      this.addMouseListener(this);
   }
   public void paint(Graphics g)
   {
      g.drawImage(immagine, x, y, this); 
   }

   private void aggiorna(int nx, int ny)
   {
      x=nx;
      y=ny;
      showStatus(x+", "+y);
      repaint();
   }

   public void mousePressed (MouseEvent me) { }
   public void mouseClicked (MouseEvent me) { aggiorna(me.getX(), me.getY()); } 
   public void mouseReleased(MouseEvent me) { }
   public void mouseEntered (MouseEvent me) { }
   public void mouseExited  (MouseEvent me) { }
}

1. repaint();

2. private void mouseClicked(MouseEvent ...) { ... }

3. showStatus(x+", "+y);

<applet code="a_duke_2.class" width="480" height="360">...</applet>

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class a_duke_2 extends Applet
{ 
   private Image immagine;
   private int   x, y;

   public void init()
   {
      x=getSize().width/2;
      y=getSize().height/2; 
      immagine=getImage(getCodeBase(), "duke.jpg");
      this.addMouseListener(new MA());
   }
   public void paint(Graphics g)
   {
      g.drawImage(immagine, x, y, this); 
   }

   private void aggiorna(int nx, int ny)
   {
      x=nx;
      y=ny;
      showStatus(x+", "+y);
      repaint();
   }

   class MA extends MouseAdapter
   {
      public void mouseClicked(MouseEvent me) { aggiorna(me.getX(), me.getY()); }
   }

}