The JApplet Class
JApplet is a simple extension of java.applet.Applet to use when creating Swing
programs designed to be used in a web browser (or
appletviewer ). As a direct subclass of Applet, JApplet is used in much the same way, with the
init( ) , start( ), and
stop( ) methods still playing
critical roles. The primary thing JApplet provides that Applet does not is the use of a JRootPane as its single display component. The properties and
methods described below should look a lot like those described in the
previous sections on JFrame and
JWindow. Figure 8-11 shows a JApplet running in
appletviewer.

Figure 8-11. A JApplet running in the SDK appletviewer
Here’s the code for this simple applet:
// SimpleApplet.java
//
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
public class SimpleApplet extends JApplet {
public void init( ) {
JPanel p = new JPanel( );
p.setLayout(new GridLayout(2, 2, 2, 2));
p.add(new JLabel("Username"));
p.add(new JTextField( ));
p.add(new JLabel("Password"));
p.add(new JPasswordField( ));
Container content = getContentPane( );
content.setLayout(new GridBagLayout( )); // Used to center the panel
content.add(p);
}
}Using JApplet in browsers is a bit trickier. You should have a browser that supports at least the 1.2 release of the JRE. You typically end up using the Java Plug-in. The Plug-in allows you to specify which version of the JRE ...