Java Eclipse probleema..

Kun yritän käynnistää ton pelin niin tulee "Exception in thread "main" java.lang.Error: Unresolved compilation problem:

at aa.main(aa.java:30)"

Onko mun koodaukses jotai vikaa?

import java.awt.Canvas;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;


import javax.swing.JFrame;


public class aa extends Canvas implements Runnable {
/**
*
*/
private static final long serialVersionUID = 1L;
public static int height = 400;
public static int width = 600;
public static String title = "Tutoriaali";
public boolean run = false;
public Thread thread;
public BufferedImage img;
public int[] pixel;
public ac screen;

public aa() {
screen = new ac();
img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
pixel = ((DataBufferInt)img.getRaster().getDataBuffer()).getData();
}

public static void main(String[] args) {
aa game = new aa();

JFrame f = new JFrame();
f.setSize(width, height);
f.setVisible(true);
f.setTitle(title);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setLocationRelativeTo(null);
f.add(game);


game.start();

}

public void start() {
if(run) return;
run = true;
thread = new Thread(this);
thread.start();


}

public void run() {
while(run) {
render();


}







public void render() {
BufferStrategy bs = this.getBufferStrategy();
if(bs == null) {
createBufferStrategy(3);
return;

}

screen.render();

for(int i=0;i<screen.pixel.length;i++) {
pixel[i] = screen.pixel[1];
}

Graphics g = bs.getDrawGraphics();
g.drawImage(img, 0, 0, width, height, null);
g.dispose();
bs.show();

}