当用户点击关闭窗口时,如何将java应用程序放在Systemtray中

我从here看到如何使用托盘.所以我用这种方式使用它：

private void checkTray() throws IOException {
    if (SystemTray.isSupported()) {
        System.out.println("system tray supported");
        tray = SystemTray.getSystemTray();
        Image image = ImageIO.read(new FileInputStream(new File("logo.png")));
        ActionListener exitListener = new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                System.out.println("Exiting....");
                System.exit(0);
            }
        };
        PopupMenu popup = new PopupMenu();
        MenuItem defaultItem = new MenuItem("Exit");
        defaultItem.addActionListener(exitListener);
        popup.add(defaultItem);
        defaultItem = new MenuItem("Open");
        defaultItem.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                setVisible(true);
                setExtendedState(JFrame.NORMAL);
            }
        });
        popup.add(defaultItem);
        trayIcon = new TrayIcon(image,"SystemTray Demo",popup);
        trayIcon.setImageAutoSize(true);
    }
    addWindowStateListener(new WindowStateListener() {

        public void windowStateChanged(WindowEvent e) {
            if (e.getNewState() == ICONIFIED) {
                try {
                    tray.add(trayIcon);
                    setVisible(false);
                    System.out.println("added to SystemTray");
                } catch (AWTException ex) {
                    System.out.println("unable to add to tray");
                }
            }
            if(e.getNewState() == WindowEvent.WINDOW_CLOSING){
               try {
                    tray.add(trayIcon);
                    setVisible(false);
                    System.out.println("added to SystemTray");
                } catch (AWTException ex) {
                    System.out.println("unable to add to system tray");
                }
            }
            if (e.getNewState() == 7) {
                try {
                    tray.add(trayIcon);
                    setVisible(false);
                    System.out.println("added to SystemTray");
                } catch (AWTException ex) {
                    System.out.println("unable to add to system tray");
                }
            }
            if (e.getNewState() == MAXIMIZED_BOTH) {
                tray.remove(trayIcon);
                setVisible(true);
                System.out.println("Tray icon removed");
            }
            if (e.getNewState() == NORMAL) {
                tray.remove(trayIcon);
                setVisible(true);
                System.out.println("Tray icon removed");
            }
        }
    });
}

并在构造函数中：

this.setDefaultCloSEOperation(JFrame.ICONIFIED);

当我点击关闭窗口时,我的应用程序没有进入系统尝试,但它自行关闭.我怎么解决呢？有人能帮我吗？