Multithreading and Game

Question

Hi guys,
I am in my first year of Java programming I have sort of hit a roadblock with an assignment we were given.
The assignment is about networking and the game that the players will play is Snakes and Ladders. I have successfully made the snakes and ladders game to work in the class Main.
I then created 2 more classes to allow the multiple players to connect and play the game. The class Server and the class Client.
Unfortunately at the moment I can only get 1 client to connect to the Server and I don't know how to get multiple connections.
I tried to re-draw the Gui for every new connection but I am not quite sure how to get each player to play the game and see the moves of the other players. Any ideas?
Class Main:_
import java.awt.event.ActionEvent;
import java.awt.event.MouseEvent;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.MouseListener;
import java.awt.image.*;
public class Main implements ActionListener{
    boolean buttonPressed = false;
    SnakesAndLaddersGUI gui;
    int[] pos;
    JButton go = new JButton("Roll Dice");
    public Main() {
        gui = new SnakesAndLaddersGUI();
        pos = new int[5];
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setSize(450, 450);
        JPanel controlPanel = new JPanel();
        controlPanel.setSize(450, 100);
        go.addActionListener(this);
        controlPanel.add(go);
        f.getContentPane().add(gui, BorderLayout.CENTER);
        f.getContentPane().add(controlPanel, BorderLayout.SOUTH);
        f.setVisible(true);
        gui.setNumberOfPlayers(5);
        for (int i = 0; i < 5; i++) {
            pos[i] = 0;
            gui.setPosition(i, 0);
        while (true) {
            if (buttonPressed) {
                move();
                buttonPressed = false;
    public void actionPerformed(ActionEvent e) {
        buttonPressed = true;
    public int PositionTest(int pos) {
        //the below conditions will lead to climbing ladders
        //or being eaten by snakes
        if (pos == 6) {
            return 16;
        } else if (pos == 11) {
            return 49;
        } else if (pos == 14) {
            return 4;
        } else if (pos == 24) {
            return 87;
        } else if (pos == 31) {
            return 9;
        } else if (pos == 35) {
            return 54;
        } else if (pos == 21) {
            return 60;
        } else if (pos == 44) {
            return 26;
        } else if (pos == 51) {
            return 67;
        } else if (pos == 56) {
            return 53;
        } else if (pos == 62) {
            return 19;
        } else if (pos == 64) {
            return 42;
        } else if (pos == 6) {
            return 16;
        } else if (pos == 73) {
            return 92;
        } else if (pos == 84) {
            return 28;
        } else if (pos == 78) {
            return 100;
        } else if (pos == 98) {
            return 80;
        } else if (pos == 95) {
            return 75;
        } else if (pos == 91) {
            return 71;
        } else {
            return pos;
    public void move() {
        try {
            int dice;
              Thread.sleep(500);
            for (int i = 0; i < 5; i++) {
                dice = (int) ((Math.random() * 10) % 6) + 1;
                if (pos[i] + dice < 100) {
                    while (dice > 0) {
                        System.out.print(dice);
                        System.out.println("\t" + i + "," + pos);
gui.setPosition(i, pos[i]++);
dice--;
Thread.sleep(100);//wait a tenth of second before climbing
//a ladder or being eaten by a snake
if (dice == 0) {//when dice is zero, the pieces have completed
//their move. we'll now test the current position
pos[i] = PositionTest(pos[i]);//set the current position
//to the position where it should be moved to
gui.setPosition(i, pos[i]);
Thread.sleep(100);
} else if (pos[i] + dice == 100) {
gui.setPosition(i, 101);
System.out.println("Player " + i + " won ");
} else if (pos[i] == 100) {
gui.setPosition(i, 101);
System.out.println("Player " + i + " won");
} catch (Exception evt) {
System.out.println(evt.getMessage());
public static void main(String[] a) {
new Main();
_*Class Server:*_import java.net.*;
import javax.swing.*;
public class Server extends Thread {
private final int PORT = 3000; //Port number
private ServerThread[] playerNumber = new ServerThread[5]; // number of people allowed to connect
private String threadName;
public Server()//Constructor
try {
ServerSocket ss = new ServerSocket(PORT);
int i = 0;
//wait for connections
while (true) {
Socket soc = ss.accept(); //Waits for client to connect
System.out.println("Connected Player " + i);
ServerThread s = new ServerThread(soc);
playerNumber[i] = s;
s.start();
threadName=s.getName();
System.out.print(threadName);
i++;
} catch (Exception e) {
e.printStackTrace(); //Displays Error if things go wrong....
public static void main(String args[]) {
new Server(); //Makes object (calls constructor)
}*_Class ServerThread_:*import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.logging.Level;
import java.util.logging.Logger;
* @author Lord Ra
class ServerThread extends Thread{
private PrintWriter out=null;
private BufferedReader in=null;
private Socket Soc;
public ServerThread(Socket soc) {
Soc=soc;
// Set up Buffered reader,writer
try {
out = new PrintWriter(Soc.getOutputStream(), true);
in=new BufferedReader(new InputStreamReader(Soc.getInputStream()));
communicateThread();
} catch (IOException ex) {
Logger.getLogger(ServerThread.class.getName()).log(Level.SEVERE, null, ex);
public void communicateThread()
while(true)
try{
String s=in.readLine();
System.out.println(s);
out.println("Your are succssefully connected to server");
catch(IOException r)

Answer 1

Class Client*
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.net.*;
import java.io.*;
public class Client implements ActionListener {
    private final int PORT = 3000; //Port number
    private PrintWriter out = null;
    private BufferedReader in = null;
    SnakesAndLaddersGUI gui;
    int[] pos;
    JButton go = new JButton("Roll Dice");
    public Client() {//Constructor
        try {
//Try to connect to server at IP address/port combination
            Socket soc = new Socket("127.0.0.1", PORT);
            //Now get the 'streams' - you use these to send messages
            out = new PrintWriter(soc.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(soc.getInputStream()));
            out.println("Hello world \n");
            out.println("I have joined this game of Snakes and Ladders \n");
            gui = new SnakesAndLaddersGUI();
            pos = new int[1];
            JFrame f = new JFrame();
            f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            f.setSize(450, 450);
            JPanel controlPanel = new JPanel();
            controlPanel.setSize(450, 100);
            go.addActionListener(this);
            controlPanel.add(go);
            f.getContentPane().add(gui, BorderLayout.CENTER);
            f.getContentPane().add(controlPanel, BorderLayout.SOUTH);
            f.setVisible(true);
            gui.setNumberOfPlayers(1);
            for (int i = 0; i < 1; i++) {
                pos[i] = 0;
                gui.setPosition(i, 0);
        } catch (Exception e) {
            e.printStackTrace(); //Displays Error if things go wrong....
    public static void main(String args[]) {
        new Client(); //Makes object (calls constructor)
    public void actionPerformed(ActionEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
}