import java.awt.*;
import java.awt.swing.*;
public class TestPanel extends JPanel {
 public TestPanel () {
  GridBagLayout gbl = new GridBagLayout();
  setLayout(gbl);
  GridBagConstraints gbc = new GridBagConstraints();
  // Fill both ways and allow expansion of all components:
  gbc.fill = GridBagConstraints.BOTH;
  gbc.weightx = 1.0;    
  gbc.weighty = 1.0;
  // Place components:
  placeComponent(0, 0, 1, 2, "A", gbl, gbc);
  placeComponent(1, 0, 1, 1, "B", gbl, gbc);
  placeComponent(0, 2, 1, 3, "C", gbl, gbc);
  placeComponent(1, 1, 1, 4, "D", gbl, gbc);
  placeComponent(2, 0, 1, 1, "E", gbl, gbc);
  placeComponent(2, 1, 1, 1, "F", gbl, gbc);
  placeComponent(2, 2, 1, 1, "G", gbl, gbc);
  placeComponent(2, 3, 1, 1, "H", gbl, gbc);
  placeComponent(2, 4, 1, 1, "I", gbl, gbc);
 }
 // Handle placement details:
 public void placeComponent 
  (int x, int y, int w, int h, 
   String s, GridBagLayout l, GridBagConstraints c) {
  c.gridx = x;          c.gridwidth = w;
  c.gridy = y;          c.gridheight = h;
  TestButton p = new TestButton(s);
  l.setConstraints(p, c);   add(p);
}}