Applet that uses a anonymous nested class to handle mouse events and draw circles. Variation on third approach to event-handling: using inner classes.

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

/** Draw circles centered where the user clicks.
 *  Uses anonymous inner classes.
 *  


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public class CircleDrawer4 extends Applet {
  public void init() {
    setForeground(Color.blue);
    addMouseListener
      (new MouseAdapter() {
         private int radius = 25;

         public void mousePressed(MouseEvent event) {
           Graphics g = getGraphics();
           g.fillOval(event.getX()-radius,
                      event.getY()-radius,
                      2*radius,
                      2*radius);
         }
      });
  }
}
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