Java Clipboard Event Listener not working

Question

I am trying to implement clipboard change event listener and I really stuck. Can't find an working example of how to implement it or whatever I find is not complete or not working. So I am trying to implement a prototype of this functionality but it has a bug... So each time when the clipboard content changed I want to see a pop up menu

import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.Toolkit;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.ClipboardOwner;
import java.awt.datatransfer.FlavorEvent;
import java.awt.datatransfer.FlavorListener;
import java.awt.datatransfer.Transferable;

import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextArea;


public class MyTextArea extends JFrame implements ClipboardOwner, FlavorListener{

    JTextArea textArea;
    Clipboard clip;
    public MyTextArea() 
    {
        this.setSize(500, 500);
        textArea =  new JTextArea(40, 40);


        clip = Toolkit.getDefaultToolkit().getSystemClipboard();
        clip.setContents(clip.getContents(null), this); 
        clip.addFlavorListener(this);



        Container cp  = this.getContentPane();
        cp.setLayout(new FlowLayout());
        cp.add(textArea);

    }

    @Override
    public void flavorsChanged(FlavorEvent e) {
        // TODO Auto-generated method stub
        JOptionPane.showMessageDialog (null, "Flavour Changed","Error", JOptionPane.ERROR_MESSAGE);


        clip.removeFlavorListener(this);
        clip.setContents(clip.getContents(null), this);
        clip.addFlavorListener(this);
    }

    @Override
    public void lostOwnership(Clipboard arg0, Transferable arg1) {
        // TODO Auto-generated method stub

    }


    public static void main(String[] args) {
        JFrame frame = new MyTextArea();

        frame.setVisible (true);
        frame.setDefaultCloseOperation (EXIT_ON_CLOSE);
    }



}

Does anyone how to make this code working properly?