package cardlayout;import java.awt.*;import java.awt.event.*;import javax.swing.*;public class Frame1 extends JFrame {  JPanel contentPane;  BorderLayout borderLayout1 = new BorderLayout();  /**Construct the frame*/  public Frame1() {    enableEvents(AWTEvent.WINDOW_EVENT_MASK);    try {      jbInit();    }    catch(Exception e) {      e.printStackTrace();    }  }  /**Component initialization*/  private void jbInit() throws Exception  {    //setIconImage(Toolkit.getDefaultToolkit().createImage(Frame1.class.getResource("[Your Icon]")));    contentPane = (JPanel) this.getContentPane();    contentPane.setLayout(borderLayout1);    this.setSize(new Dimension(400, 300));    this.setTitle("CardLayout演示程序");  }  /**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);    }  }}