package jinternalframedemo;import java.awt.*;import java.awt.event.*;import javax.swing.*;/** * <p>Title: </p> * <p>Description: </p> * <p>Copyright: Copyright (c) 2002</p> * <p>Company: </p> * @author unascribed * @version 1.0 */public class MainFrame extends JFrame {//  private JPanel contentPane;  private JDesktopPane desktop = new JDesktopPane();//  private BorderLayout borderLayout1 = new BorderLayout();  private JMenuBar jMenuBar1 = new JMenuBar();  private JMenu jMenu1 = new JMenu();  private JMenuItem jMenuItem1 = new JMenuItem();  //Construct the frame  public MainFrame() {    enableEvents(AWTEvent.WINDOW_EVENT_MASK);    try {      jbInit();    }    catch(Exception e) {      e.printStackTrace();    }  }  //Component initialization  private void jbInit() throws Exception  {    //setIconImage(Toolkit.getDefaultToolkit().createImage(MainFrame.class.getResource("[Your Icon]")));//    contentPane = (JPanel) this.getContentPane();//    contentPane.setLayout(borderLayout1);    desktop.putClientProperty("JDesktopPane.dragMode", "outline");    this.setContentPane(desktop);    this.setJMenuBar(jMenuBar1);    this.setSize(new Dimension(400, 300));    this.setTitle("JInternalFrameDemo");    jMenu1.setFont(new java.awt.Font("Dialog", 0, 12));    jMenu1.setText("Option");    jMenuItem1.setFont(new java.awt.Font("Dialog", 0, 12));    jMenuItem1.setText("Add Frame");    jMenuItem1.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        jMenuItem1_actionPerformed(e);      }    });    jMenuBar1.add(jMenu1);    jMenu1.add(jMenuItem1);  }  //Overridden so we can exit when window is closed  protected void processWindowEvent(WindowEvent e) {    super.processWindowEvent(e);    if (e.getID() == WindowEvent.WINDOW_CLOSING) {      System.exit(0);    }  }  void jMenuItem1_actionPerformed(ActionEvent e) {    OwnInternalFrame frame = new OwnInternalFrame();    frame.setVisible(true); //necessary as of kestrel    desktop.add(frame);    try {      frame.setSelected(true);    } catch (java.beans.PropertyVetoException err) {      err.printStackTrace();    }  }}