// An applet that appears on the page as a button that says
// "Click me".  When the button is clicked, an informational
// dialog box appears to say Hello from Swing.

import javax.swing.*;    // Swing GUI classes are defined here.
import java.awt.event.*; // Event handling class are defined here.

public class HelloSwing extends JApplet implements ActionListener {

   public void init() {
         // This method is called by the system before the applet
         // appears.  It is used here to create the button and add
         // it to the "content pane" of the JApplet.  The applet
         // is also registered as an ActionListener for the button.

      JButton bttn = new JButton("Click Me!");
      bttn.addActionListener(this);
      getContentPane().add(bttn);

   } // end init()
   
   public void actionPerformed(ActionEvent evt) {
         // This method is called when an action event occurs.
         // In this case, the only possible source of the event
         // is the button.  So, when this method is called, we know
         // that the button has been clicked.  Respond by showing
         // an informational dialog box.  The dialog box will
         // contain an "OK" button which the user must click to
         // dismiss the dialog box.

      String title = "Greetings";  // Shown in title bar of dialog box.
      String message = "Hello from the Swing User Interface Library.";
      JOptionPane.showMessageDialog(null, message, title,
                                     JOptionPane.INFORMATION_MESSAGE);
   } // end actionPerformed()

} // end class HelloSwing