How Can I Make Keyboard In Java Using Netbeans?

import javax.swing.*; 
 import java.awt.event.*; 
 public class YQuestions extends JFrame implements KeyListener 
 { 
 YQuestions(){ 
 setDefaultCloseOperation(EXIT_ON_CLOSE); 
 setSize(500,500); 
 addKeyListener(this); 
 setVisible(true); 
 } 
 public void keyPressed(KeyEvent ke){ 
 if(ke.isAltDown() && ke.getKeyCode()==KeyEvent.VK_R){ 
 new JOptionPane().showMessageDialog(this, "You pressed Alt-R"); 
 } 
 } 
 public void keyReleased(KeyEvent ke){} 
 public void keyTyped(KeyEvent ke){} 
 public static void main(String[] args){ 
 new YQuestions(); 
 } 
 }