codeing help random pixels

Display.java

import java.awt.Canvas;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferInt;
import javax.swing.JFrame;
import com.mime.soilderattack.graphics.Render;
import com.mime.soilderattack.graphics.Screen;
import java.awt.Toolkit;

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 = "Soilder Attack Pre-Alpha 0.01";

private Thread thread;
private Screen screen;
private BufferedImage img;
private Render render;
private boolean running = false;
private int[] pixels;

public Display() {
screen = new Screen(WIDTH, HEIGHT);
img = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
pixels = ((DataBufferInt)img.getRaster().getDataBuffer()).g etData();
}

private void start() {
if (running)
return;
running = true;
thread = new Thread(this);
thread.start();

}

private 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_CLOS E);
frame.setSize(width, height);
frame.setLocationRelativeTo(null);
frame.setResizable(false);
frame.setVisible(true);

System.out.println("Running...");

game.start();
}

}

Render.java

package com.mime.soilderattack.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];
}
}

}
}

screen.java

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() {
for (int i = 0; i < width * height; i++) {
pixels[i] = 0;
}

for (int i = 0; i < 200; i++) {

}
}
}

can you tell me what to do and where to put it i am new to this coding