Re: How to change JPanels?

So now my previous sample looks like this. I hope I'm doing this
right now. I'm not sure if it's the most efficient syntax but it
works.

... imports elided ...
public class TestWindow {

      InnerTestWindow win = null;

      protected class InnerTestWindow extends JFrame {

           protected CardLayout cardLayout = null;
           protected Container contentPane = null;
           protected JPanel panelOne = null;
           protected JPanel panelTwo = null;
           private JTextArea dummyTextOne = null;
           private JTextArea dummyTextTwo = null;

           protected InnerTestWindow() {
                contentPane = getContentPane();
                contentPane.setLayout(new CardLayout());
                cardLayout = (CardLayout)contentPane.getLayout();
                MenuBar menuBar = new MenuBar();
                Menu menu = new Menu("Test");
                addMenuItem(menu,"First","FirstItem",new
FirstItemListener());
                menuBar.add(menu);
                setMenuBar(menuBar);

setDefaultCloseOperation( WindowConstants.DISPOSE_ON_CLOSE );
                setSize(600, 600);
                setLocation(100, 100);
                panelOne = new JPanel();
                contentPane.add(panelOne,"Panel One");
                dummyTextOne = new JTextArea("Panel One");
                panelOne.add(dummyTextOne);
                panelTwo = new JPanel();
                contentPane.add(panelTwo,"Panel Two");
                dummyTextTwo = new JTextArea("Panel Two");
                panelTwo.add(dummyTextTwo);
                setContentPane(contentPane);
                loadOne();
           }

           private void addMenuItem(Menu menu, String menuItemTitle,
String menuItemName, ActionListener menuListener) {
                MenuItem menuItem = new MenuItem(menuItemTitle);
                menuItem.setActionCommand(menuItemName);
                menuItem.addActionListener(menuListener);
                menu.add(menuItem);
           }

           protected class FirstItemWorker extends SwingWorker {
                BufferedImage[] renderedPngPages = null;
                int waitTime;
                protected FirstItemWorker(int waitTimeIn) {
                     waitTime = waitTimeIn;
                }
                protected Integer doInBackground() {
                     long t0, t1;
                     t0 = System.currentTimeMillis();
                     do {
                          t1 = System.currentTimeMillis();
                     } while ((t1 - t0)< (waitTime));
                     return 0;
                }
                protected void done() {
                     if (isCancelled()) {
                          return;
                     }
                     loadOne();
                }
           }

           private class FirstItemListener implements ActionListener {
                public void actionPerformed(ActionEvent ev) {
                     loadTwo();
                     FirstItemWorker fiw = new FirstItemWorker(3000);
                     fiw.execute();
                }
           }

           protected void loadOne() {
                cardLayout.show(contentPane, "Panel One");
                repaint();
           }

           public void loadTwo() {
                cardLayout.show(contentPane, "Panel Two");
                repaint();
           }
      }

      public void createWindow() {
           win = new InnerTestWindow();
           win.setVisible(true);
      }

      public static void main(String[] args) throws Exception {
           TestWindow testWin = new TestWindow();
           testWin.createWindow();
      }

}