VerySimpleChatServer.java

import java.io.*;
import java.net.*;
import java.util.*;

public class VerySimpleChatServer{
    ArrayList clientOutputStreams;
    
    public class ClientHandler implements Runnable{
        BufferedReader reader;
        Socket sock;
        
        public ClientHandler(Socket clientSocket){
            try{
                sock = clientSocket;
                InputStreamReader isReader = new InputStreamReader(sock.getInputStream());
                reader = new BufferedReader(isReader);
            } catch(Exception ex) { ex.printStackTrace(); }
        } //close constructor
        
        public void run(){
            String message;
            try{
                while ((message = reader.readLine()) != null ){
                    System.out.println("read" + message);
                    tellEveryone(message);
                } //close while
            } catch(Exception ex) {ex.printStackTrace();}
        } // close run
    } // close inner class
    
    public static void main(String[] args){
        new VerySimpleChatServer().go();
    }
    
    public void go(){
        clientOutputStreams = new ArrayList();
        
        try{
            ServerSocket serverSock = new ServerSocket(5000);
            
            while(true){
                Socket clientSocket = serverSock.accept();
                PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());
                clientOutputStreams.add(writer);
                
                Thread t = new Thread(new ClientHandler(clientSocket));
                t.start(); 
                System.out.println("got a connection");
            }
        } catch (Exception ex){
            ex.printStackTrace();
        }
    }// close go
        
    public void tellEveryone(String message){
        Iterator it = clientOutputStreams.iterator();
        while(it.hasNext()){
            try{
                PrintWriter writer = (PrintWriter) it.next();
                writer.println(message);
                writer.flush();
            } catch (Exception ex){
                ex.printStackTrace();
            }
        } // end while
        
    } //close tellEveryOne
}