Thread: Pls help with my game pixel draw

What is wrong with my project?When run it gives me gray screen

First Class--------------
 
package com.mime.minefront;
 
import java.awt.Canvas;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferInt;
import java.awt.Graphics;
import javax.swing.JFrame;
 
import com.mime.minefron.graphics.Render;
import com.mime.minefron.graphics.Screen;
 
public class Display extends Canvas implements Runnable {
	private static final long serialVersionUID = 1L;
 
	public static final int WIDTH = 800;
	public static final int HEIGHT = 600;
	public static final String TITLE = "GAME Fazkyy Pre-Alpha 0.0.1";
 
	private Thread thread;
	private Screen screen;
	private BufferedImage img;
	private Render render;
	private boolean running = false;
	private int[] pixels;
 
	private Display() {
		screen = new Screen(WIDTH, HEIGHT);
		img = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
		pixels = ((DataBufferInt)img.getRaster().getDataBuffer()).getData();
	}
 
 
	private void start() {
		if (running)
			return;
		running = true;
		thread = new Thread();
		thread.start();
 
		System.out.println("Working!");
	}
 
 
 
	public void stop() {
		if (!running)
			return;
		running = false;
		try {
			thread.join();
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(0);
		}
	}
 
	public void run () {
		while(running) {
			tick();
			Render();
		}
	}
 
    private void tick() {
 
    }
 
    private void Render() {
    		BufferStrategy bs = this.getBufferStrategy();
    		if (bs == null) {
    			createBufferStrategy(3);
    			return;
    		}
 
    		screen.render();
 
    		for (int i = 0; i<WIDTH * HEIGHT; i++) {
    			pixels[i] = screen.pixels[i];
 
    		}
 
    		Graphics g = bs.getDrawGraphics();
    		g.drawImage(img, 0, 0, WIDTH, HEIGHT, null);
    		g.dispose();
    		bs.show(); 		
 
    }
 
	public static void main(String [] args) {
		Display game = new Display();
		JFrame frame = new JFrame();
		frame.add(game);
		frame.pack();
		frame.setTitle(TITLE);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setSize(WIDTH, HEIGHT);
		frame.setLocationRelativeTo(null);
		frame.setResizable(false);
		frame.setVisible(true);
 
		System.out.println("Running...");
 
		game.start();
	}
 
 
}
 
Second Class-------------
 
package com.mime.minefron.graphics;
 
public class Render {
	public final int width;
	public final int height;
	public final int[]pixels;
 
	public Render(int width, int height) {
		this.width = width;
		this.height = height;
		pixels = new int[width * height];
	}
 
	public void draw(Render render, int xOffset, int yOffset) {
		for (int y = 0; y<render.height; y++) {
			int yPix = y + yOffset;
 
				for(int x = 0; x <render.width; x++) {
					int xPix = x + xOffset;
 
					pixels[xPix + yPix * width] = render.pixels[x+y*render.width];
				}
	       }
 
 
	 }
 
}
 
Third Class------
package com.mime.minefron.graphics;
 
import java.util.Random;
 
 
public class Screen extends Render {
 
	private Render test;
 
	public Screen(int width, int height) {
		super(width, height);
		Random random = new Random();
		test = new Render(256, 256);
		for(int i = 0; i < 256*256; i++) {
			test.pixels[i] = random.nextInt();
 
		}
 
	}
 
	public void render() {
		draw(test, 250, 250);
	}
 
}

Okay i edit it.Can you help me now ?Тhanks in advance

I just wached tutorial in youtube and i fix all bug and still nothing.Im novice in java programing so i need little help.

Ahh i dont know i will go read more about codes.Thanks anyway