<:> Interactive Hello World applet

  import javax.swing.*;
  import java.awt.*;
  import java.awt.event.*;

  class HelloWorldPanel extends JPanel implements MouseListener {
     MouseEvent event;

     public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawString("Hello World", 10, 20);
        if (event != null) g.fillOval(event.getX(), event.getY(), 20, 20);
     }

     public void mousePressed(MouseEvent event) {
        this.event = event;
        repaint();
     }

     public void mouseReleased(MouseEvent event) { }
     public void mouseClicked(MouseEvent event) { }
     public void mouseEntered(MouseEvent event) { }
     public void mouseExited(MouseEvent event) { }

  }

  public class HelloWorld extends JApplet {
     public void init() {
        HelloWorldPanel appletPanel = new HelloWorldPanel();
        appletPanel.addMouseListener(appletPanel);
        appletPanel.setBackground(Color.pink);
        getContentPane().add(appletPanel);
     }
  }