Klient + serwer

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.Reader;
import java.net.Socket;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.ScrollPaneConstants;

public class Klient {
	private JTextArea textArea;
	private JTextField textFiled;
	private JFrame frame;
	private JPanel panel;
	private JButton button;
	
	private PrintWriter writer;
	private BufferedReader reader;
	Socket socket;
	
	public static void main(String[] args) {
		new Klient().doDziela();
	}
	
	private void doDziela() {
		frame = new JFrame();
		panel = new JPanel();
		textFiled = new JTextField(20);
		button = new JButton("Kliknij mnie");
		button.addActionListener(new MyButtonListener());
		textArea = new JTextArea(15, 50);
		textArea.setLineWrap(true);
		textArea.setWrapStyleWord(true);
		textArea.setEditable(false);
		JScrollPane scpane = new JScrollPane(textArea);
		scpane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
		scpane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
		
		panel.add(scpane);
		panel.add(textFiled);
		panel.add(button);
		frame.add(panel);
		
		this.konfigurujKomunikacje();
		Thread watekOdbiorcy = new Thread(new OdbiorcaKomunikatow());
		watekOdbiorcy.start();
		
		frame.pack();
		frame.setLocationRelativeTo(null);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}
	
	private void konfigurujKomunikacje() {
		try {
			socket = new Socket("127.0.0.1", 5000);
			reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
			writer = new PrintWriter(socket.getOutputStream());
			System.out.println("Konfiguracja komunikacji przebiegla pomyslnie");
		} 
		catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	private class MyButtonListener implements ActionListener {
		public void actionPerformed(ActionEvent arg0) {
			try {
				writer.println(textFiled.getText());
				writer.flush();
			}
			catch(Exception e) {
				e.printStackTrace();
			}
			
			textFiled.setText("");
			textFiled.requestFocus();
		}
	}
		
	class OdbiorcaKomunikatow implements Runnable {
		public void run() {
			String widomosc;
			try {
				while((widomosc = reader.readLine()) != null) {
					textArea.append(widomosc + "\n");
				}
			} 
			catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;

public class Serwer {
	private ArrayList strumienieWyjsciowe;
	
	public static void main(String[] args) {
		new Serwer().doRoboty();
	}
	
	public void doRoboty() {
		strumienieWyjsciowe = new ArrayList();
		try{
			ServerSocket servSocket = new ServerSocket(5000);
			
			while(true) {
				Socket gniazdoKlienta = servSocket.accept();
				PrintWriter pisarz = new PrintWriter(gniazdoKlienta.getOutputStream());
				strumienieWyjsciowe.add(pisarz);
				
				Thread t = new Thread(new ObslugaKlientow(gniazdoKlienta));
				t.start();
				System.out.println("Mamy polaczenie");
			}
		}
		catch (Exception e) {
			e.printStackTrace();
		}
	}
	public void rozeslijDoWszystkic(String message) {
		for(Object x : strumienieWyjsciowe) {
			PrintWriter pisarz = (PrintWriter) x;
			pisarz.println(message);
			pisarz.flush();
		}
	}
	
	class ObslugaKlientow implements Runnable {
		BufferedReader czytelnik;
		Socket gniazdo;
		
		public ObslugaKlientow(Socket gniazdoK) {
			try {
				gniazdo = gniazdoK;
				czytelnik = new BufferedReader(new InputStreamReader(gniazdo.getInputStream()));
			} 
			catch (IOException e) {
				e.printStackTrace();
			}
		}

		public void run() {
			String wiadomosc;
			try {
				while((wiadomosc = czytelnik.readLine()) != null) {
					System.out.println("Odczytano: " + wiadomosc);
					rozeslijDoWszystkic(wiadomosc);
				}
			} 
			catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
}