ToolTip of a ComboBox

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.plaf.basic.*;

    public class ToolTipComboBox extends JFrame {
   
     String[] items = {"jw" ,"ja" ,"la" };
     String[] tooltips = {"Javanese ","Japanese ","Latin "};
   
         public ToolTipComboBox() {
         super("ToolTip ComboBox Example");
       
         JComboBox combo = new JComboBox(items);
         combo.setRenderer(new MyComboBoxRenderer());
       
         getContentPane().setLayout(new FlowLayout());
         getContentPane().add(combo);
     }
   
         class MyComboBoxRenderer extends BasicComboBoxRenderer {
         public Component getListCellRendererComponent( JList list,
             Object value, int index, boolean isSelected, boolean cellHasFocus) {
                 if (isSelected) {
                 setBackground(list.getSelectionBackground());
                 setForeground(list.getSelectionForeground());
                     if (-1 < index) {
                     list.setToolTipText(tooltips[index]);
                 }
                 } else {
                 setBackground(list.getBackground());
                 setForeground(list.getForeground());
             }
             setFont(list.getFont());
             setText((value == null) ? "" : value.toString());
             return this;
         }
     }
   
         public static void main (String args[]) {
         ToolTipComboBox frame = new ToolTipComboBox();
             frame.addWindowListener(new WindowAdapter() {
                 public void windowClosing(WindowEvent e) {
                 System.exit(0);
             }
         });
         frame.setSize(200, 140);
         frame.setVisible(true);
     }
}