Also available as KeyHandler.java

/**
 * A Simple stand-alone GUI program based on Swing.
 *  
 * Using a KeyListener with a text field
 *
 * @author Dave Hollinger
 * @version 1.0
 */

import javax.swing.*;
import java.awt.*;       // needed for Container
import java.awt.event.*;  // needed for event types (listeners)


class KeyHandler extends JFrame implements KeyListener {

  // The textfield must not be anonymouse, since we want to        
  // be able to modify it from event handlers

  JTextField jt;

  public static void main(String [] args) {
        KeyHandler me = new KeyHandler();
  }

  // Constructor sets up the window and gets things rolling.
  KeyHandler() {

        Container c = getContentPane();
        // set up layout manager
        c.setLayout(new BorderLayout(10,10));
        
        // add single text Area (use default colors, etc)
        jt = new JTextField();
        // set up to listen for events
        jt.addKeyListener(this);

        c.add(jt,BorderLayout.NORTH);


        // establish what happens when the window is closed
        // (without this the program would keep running!)
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        // set the size
        setSize(200,200);
        // turn it on
        setVisible(true);
  }

  // here are the methods required by KeyListener
  // (there is only one!)

  public void keyPressed(KeyEvent e) {
  }

  public void keyReleased(KeyEvent e) {
  }

  public void keyTyped(KeyEvent e) {
        char c = e.getKeyChar();
        jt.setText("key text: " + c);
  }


}