Como usar una grid bag layout en un applet de java

Veamos un ejemplo de cómo funciona un grid bag layout.

package masterdavidjavabasico;

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

/*
<APPLET
    CODE=gridbag.class
    WIDTH=400
    HEIGHT=80 >
</APPLET>
*/

public class gridbag extends Applet implements ActionListener
{
    Button button1, button2, button3;
    TextField text1;

    public void init()
    {
        GridBagLayout gridbag = new GridBagLayout();
        GridBagConstraints constraints = new GridBagConstraints();
        setLayout(gridbag);
        constraints.weighty = 1;
        constraints.fill = GridBagConstraints.BOTH;

        constraints.weightx = 1;
        button1 = new Button("Boton 1");
        gridbag.setConstraints(button1, constraints);
        button1.setActionCommand("boton 1");
        add(button1);
        button1.addActionListener(this);

        constraints.weightx = 2;
        button2 = new Button("Boton 2");
        gridbag.setConstraints(button2, constraints);
        button2.setActionCommand("boton 2");
        add(button2);
        button2.addActionListener(this);

        constraints.weightx = 1;
        button3 = new Button("Boton 3");
        constraints.gridwidth = GridBagConstraints.REMAINDER;
        gridbag.setConstraints(button3, constraints);
        button3.setActionCommand("boton 3");
        add(button3);
        button3.addActionListener(this);

        text1 = new TextField();
        constraints.gridwidth = GridBagConstraints.REMAINDER;
        gridbag.setConstraints(text1, constraints);
        add(text1);
    }

    public void actionPerformed(ActionEvent e)
    {
        text1.setText("Hizo clic sobre " + ((Button) e.getSource()).getActionCommand());
    }                 
}