code for Using system tray

import java.awt.Image;
import java.awt.MenuItem;
import java.awt.PopupMenu;
import java.awt.SystemTray;
import java.awt.Toolkit;
import java.awt.TrayIcon;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JOptionPane;

public class SystemTrayDemo {
public static void main(String[] args)throws Exception {
if (!SystemTray.isSupported()) {
System.out.println("SystemTray is not supported");
return;
}

SystemTray tray = SystemTray.getSystemTray();
Toolkit toolkit = Toolkit.getDefaultToolkit();
Image image = toolkit.getImage("trayIcon.jpg");

PopupMenu menu = new PopupMenu();

MenuItem messageItem = new MenuItem("Show Message");
messageItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(null, "www.java2s.com");
}
});
menu.add(messageItem);

MenuItem closeItem = new MenuItem("Close");
closeItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
menu.add(closeItem);
TrayIcon icon = new TrayIcon(image, "SystemTray Demo", menu);
icon.setImageAutoSize(true);

tray.add(icon);
}
}