Un problema con il player

import javax.swing.JFrame;

public class Game {
	
	public static void main(String[] args) {
		JFrame window = new JFrame("nfjkbnfd");
		window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		window.setContentPane(new GamePanel());
		
		window.pack();
		window.setVisible(true);
		
	}


}

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

public class GamePanel extends JPanel implements Runnable, KeyListener{
	
	//fields
	public static final int WIDTH = 600;
	public static final int HEIGHT = 600;
	
	private Thread thread; 
	private boolean running;
	
	private BufferedImage image;
	private Graphics2D g;
	
	private int FPS = 30;
	private double averageFPS;
	
	private Player player;
	
	//constructor
	public GamePanel() {
		super();
		setPreferredSize(new Dimension(WIDTH, HEIGHT));
		setFocusable(true);
		requestFocus();
	}
	
	//functions
	public void addNotify() {
		super.addNotify();
		if(thread == null) {
			thread = new Thread(this);
			thread.start();
		}
		addKeyListener(this);
	}

	@Override
	public void run() {
		
		running = true;
		
		image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_BGR);
		g = (Graphics2D) image.getGraphics();
		
		player = new Player();
		
		//FPS
		long startTime;
		long URDTimeMillis;
		long waitTime;
		long totalTime = 0;
		
		int frameCount = 0;
		int maxFrameCount = 30;
		
		long targetTime = 1000 / FPS;
		
		//GAMe LOOP
		while (running) {
			//FPS
			startTime = System.nanoTime();
			
			gameUpdate();
			gameRender();
			gameDraw();
			
			URDTimeMillis = (System.nanoTime() - startTime) / 1000000;
			waitTime = targetTime - URDTimeMillis;
			
			try {
				Thread.sleep(waitTime);
			}
			catch(Exception e) {
			}
			totalTime += System.nanoTime() - startTime;
			frameCount++;
			if(frameCount == maxFrameCount) {
				averageFPS = 1000.0 / ((totalTime / frameCount) / 1000000);
				frameCount = 0;
				totalTime = 0;
				
			}
		}
		
	}

	private void gameUpdate() {
		player.update();
	}
	
	private void gameRender() {
		g.setColor(new Color(0, 100, 255));
		g.fillRect(0, 0, WIDTH, HEIGHT);
		g.setColor(Color.BLACK);
		g.drawString("FPS" + averageFPS, 10, 10);
		//end FPS
		player.draw(g);
	}
	

	private void gameDraw() {
		Graphics g2 = this.getGraphics();
		g2.drawImage(image, 0, 0, null);
		g2.dispose();
	}

	@Override
	public void keyPressed(KeyEvent key) {
		int keyCode = key.getKeyCode();
		if(keyCode == KeyEvent.VK_LEFT) {
			player.setLeft(true);
		}
		if(keyCode == KeyEvent.VK_RIGHT) {
			player.setRight(true);
		}
		if(keyCode == KeyEvent.VK_UP) {
			player.setUp(true);
		}
		if(keyCode == KeyEvent.VK_DOWN) {
			player.setDown(true);
		}
	}

	@Override
	public void keyReleased(KeyEvent key) {
		int keyCode = key.getKeyCode();
		if(keyCode == KeyEvent.VK_LEFT) {
			player.setLeft(false);
		}
		if(keyCode == KeyEvent.VK_RIGHT) {
			player.setRight(false);
		}
		if(keyCode == KeyEvent.VK_UP) {
			player.setUp(false);
		}
		if(keyCode == KeyEvent.VK_DOWN) {
			player.setDown(false);
		}
	}

	@Override
	public void keyTyped(KeyEvent key) {
		
	}
}

import java.awt.*;

public class Player {
	
	//FIELDS
	private int x;
	private int y;
	private int r;
	
	private boolean left;
	private boolean right;
	private boolean up;
	private boolean down;
	
	private int dx;
	private int dy;
	private int speed;
	
	private int lives;
	private Color color1;
	private Color color2;
	
	//CONSTRUCTOR
	public Player() {
		x = GamePanel.WIDTH / 2;
		y = GamePanel.HEIGHT / 2;
		r = 5;
		
		dx = 0;
		dy = 0;
		speed = 5;
		
		lives = 3;
		color1 = Color.WHITE;
		color2 = Color.RED;
	}
	
	//FUNCTIONS
	
	public void setLeft(boolean b) {left = b;}
	public void setRight(boolean b) {right = b;}
	public void setUp(boolean b) {up = b;}
	public void setDown(boolean b) {down = b;}
	
	public void update() {
		if(left) {
			dx = -speed;
		}
		if(right) {
			dx = speed;
		}
		if(up) {
			dy = -speed;
		}
		if(down) {
			dy = speed;
		}
		x += dx;
		y += dy;
		
		if(x < r) x = r;
		if(y < r) y = r;
		if(x < GamePanel.WIDTH - r) x = GamePanel.WIDTH - r;
		if(y < GamePanel.HEIGHT - r) y = GamePanel.HEIGHT - r;
		
		dx = 0;
		dy = 0;
	}
	public void draw(Graphics2D g) {
		g.setColor(color1);
		g.fillOval(x - r, y - r, 2 * r, 2 * r);
		g.setStroke(new BasicStroke(3)); //3 pixels
		g.setColor(color1.darker());
		g.drawOval(x - r, y - r, 2 * r, 2 * r);
		g.setStroke(new BasicStroke(1)); //3 pixels
	}
		

}