How to use Java Tooltip

import java.awt.BorderLayout;
import java.awt.Container;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JToolTip;
import java.awt.Color;

public class TooltipSample {

     public static void main(String args[]) {
        String title = "Tooltip Sample";
        JFrame frame = new JFrame(title);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        Container container = frame.getContentPane();
        JPanel panel = new JPanel();
        panel.setToolTipText( "Tooltip
Message");
        container.add(panel, BorderLayout.CENTER);

        JButton button = new JButton( "Hello World") {
             public JToolTip createToolTip() {
                JToolTip tip = super.createToolTip();
                tip.setBackground(Color.yellow);
                tip.setForeground(Color.green);
                 return tip;
            }

             public boolean contains( int x, int y) {
                 if (x < 100) {
                    setToolTipText( "Got Green Eggs?");
                } else {
                    setToolTipText( "Got Ham?");
                }
                 return super.contains(x, y);
            }
        };
        button.setToolTipText( "Hello World");
        frame.getContentPane().add(button, BorderLayout.NORTH);

        frame.setSize(300, 150);
        frame.setVisible( true);
    }
}