Chat klient-serwer. Nie tworzy się nowy wątek dla drugiego klienta.

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;


public class Serwer 
{
	static List<Handler> listaKlientow = new ArrayList<Handler>();
	
	public static void main(String[] args)
	{
		try 
		{
			int i = 1;
			final ServerSocket s = new ServerSocket(8189);
			
			while(true)
			{
				final Socket incoming = s.accept();
				
				//System.out.println("test1");
				Handler handler = new Handler(incoming);
				//System.out.println("test2");
				listaKlientow.add(handler);
				handler.run();
				System.out.println("Serwer: Utworzyłem wątek " + i);
				i++;
			}
		}
		catch(IOException exception) {exception.printStackTrace();}
	}
	
	public synchronized void rozsylanie(String line)
	{
		for(Handler h : listaKlientow)
		{
			System.out.println(line);
			h.wysylanie(line);
		}
	}
}

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;


public class Handler extends Thread
{
	private Socket incoming;
	private PrintWriter out;

	Serwer serwer = new Serwer();
	
	public Handler(Socket socket)
	{
		incoming = socket;
	}
	
	public void run()
	{
		try
		{
			try
			{
				final InputStream inStream = incoming.getInputStream();
				final OutputStream outStream = incoming.getOutputStream();
				
				final Scanner in = new Scanner(inStream);
				out = new PrintWriter(outStream, true);
				
				String line;
				
				out.print("Serwer: Witaj! \n");
				
				while(in.hasNextLine())
				{
					//wczytywanie
					line = in.nextLine();
					System.out.println("Serwer: Wczytałem linię: " + line);
					serwer.rozsylanie(line);
				}
			}
			finally
			{
				Serwer.listaKlientow.remove(this);
				System.out.println("Serwer: Usunalem handler: " + this);
				incoming.close();
			}
		}
		catch(IOException exception) {exception.printStackTrace();}
	}

	public void wysylanie(String line) 
	{
		out.println(line);
	}
}