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

public class KeyTest extends JPanel implements KeyListener {
	private int x = 50, y = 20;

	public KeyTest() {
		setPreferredSize(new Dimension(150, 150));
		setFocusable(true);
		addKeyListener(this);
	}

	@Override
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		g.drawString("HELLO WORLD!", x, y);
	}

	public void keyTyped(KeyEvent e) {
		int k = e.getKeyChar();
		if (k == 'u') {
			y -= 10;
		} else if (k == 'd') {
			y += 10;
		} 
		System.err.printf("key = %d%n", k);
		repaint();
	}
	public void keyReleased(KeyEvent e) {}
	public void keyPressed(KeyEvent e) {
		//	    int k = e.getKeyCode();
		//	    if (k == VK_U) {
		//	      y -= 10;
		//	    } else if (k == VK_D) {
		//	      y += 10;
		//	    } 
		//	    System.err.printf("key=%d", k);
		//	    repaint();
	}

	public static void main(String[] args) {
		SwingUtilities.invokeLater(() -> {
			JFrame frame = new JFrame("Key Test");
			frame.add(new KeyTest());
			frame.pack();
			frame.setVisible(true);
			frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		});
	}
}