package menubar;import java.awt.*;import java.awt.event.*;import javax.swing.*;public class Frame1 extends JFrame {  JPanel contentPane;  MenuBar menuBar1 = new MenuBar();  Menu menu1 = new Menu();  MenuItem menuItem1 = new MenuItem();  Menu menu2 = new Menu();  CheckboxMenuItem checkboxMenuItem1 = new CheckboxMenuItem();  Menu menu3 = new Menu();  MenuItem menuItem2 = new MenuItem();  MenuItem menuItem4 = new MenuItem();  MenuItem menuItem5 = new MenuItem();  Menu menu4 = new Menu();  MenuItem menuItem3 = new MenuItem();  MenuItem menuItem6 = new MenuItem();  FlowLayout flowLayout1 = new FlowLayout();  Label label1 = new Label();  /**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(flowLayout1);    this.setResizable(false);    this.setSize(new Dimension(326, 156));    this.setTitle("主菜單演示程序");    menu1.setLabel("文件");    menuItem1.setLabel("退出");    menuItem1.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        menuItem1_actionPerformed(e);      }    });    menu2.setLabel("視圖");    checkboxMenuItem1.setLabel("顯示文本");    checkboxMenuItem1.setState(true);    checkboxMenuItem1.addItemListener(new java.awt.event.ItemListener() {      public void itemStateChanged(ItemEvent e) {        checkboxMenuItem1_itemStateChanged(e);      }    });    menu3.setLabel("改變背景色");    menuItem2.setLabel("黑色");    menuItem2.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        menuItem2_actionPerformed(e);      }    });    menuItem4.setLabel(" 紅色");    menuItem4.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        menuItem4_actionPerformed(e);      }    });    menuItem5.setLabel(" 白色");    menuItem5.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        menuItem5_actionPerformed(e);      }    });    menu4.setLabel("改變標題");    menuItem3.setLabel("中文");    menuItem3.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        menuItem3_actionPerformed(e);      }    });    menuItem6.setLabel(" 英文");    menuItem6.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        menuItem6_actionPerformed(e);      }    });    label1.setText("主菜單演示程序");    menuBar1.add(menu1);    menuBar1.add(menu2);    menu1.add(menuItem1);    menu2.add(menu3);    menu2.add(menu4);    menu2.addSeparator();    menu2.add(checkboxMenuItem1);    menu3.add(menuItem2);    menu3.add(menuItem4);    menu3.add(menuItem5);    menu4.add(menuItem3);    menu4.add(menuItem6);    contentPane.add(label1, null);    setMenuBar(menuBar1);  }  /**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 menuItem1_actionPerformed(ActionEvent e) {System.exit(0);  }  void menuItem2_actionPerformed(ActionEvent e) {  contentPane.setBackground(Color.black);  }  void menuItem4_actionPerformed(ActionEvent e) {  contentPane.setBackground(Color.red);  }  void menuItem5_actionPerformed(ActionEvent e) {  contentPane.setBackground(Color.white);  }  void menuItem3_actionPerformed(ActionEvent e) {  this.setTitle("主菜單演示程序");  }  void menuItem6_actionPerformed(ActionEvent e) {  this.setTitle("Menu Bar Pro");  }  void checkboxMenuItem1_itemStateChanged(ItemEvent e) {  if (checkboxMenuItem1.getState())    label1.setVisible(true);  else    label1.setVisible(false);  }}