Classe Servidor

package br.com.uol.xpg.wyalves.chat2;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;

public class Server extends Thread {

    private static ArrayList<BufferedWriter> clients;
    private static ServerSocket server;
    private Socket client;
    private String name;
    private InputStream in;
    private InputStreamReader inr;
    private BufferedReader bfr;

    public Server(Socket client) {
        this.client = client;
        try {
            in = client.getInputStream();
            inr = new InputStreamReader(in);
            bfr = new BufferedReader(inr);
        } catch (Exception e1) {
            Logger.getLogger(Server.class.getName()).log(Level.SEVERE, null, e1);
        }
    }

    public void run() {
        try {
            OutputStream out = this.client.getOutputStream();
            Writer outw = new OutputStreamWriter(out);
            BufferedWriter bfw = new BufferedWriter(outw);
            clients.add(bfw);

            String msg = name = bfr.readLine();
            while (!"Sair!".equalsIgnoreCase(msg) && msg != null) {
                msg = bfr.readLine();
                sendToAll(bfw, msg);
                System.out.println(msg);
            }
        } catch (Exception e2) {
            Logger.getLogger(Server.class.getName()).log(Level.SEVERE, null, e2);
        }
    }

    private void sendToAll(BufferedWriter bwSaida, String msg) {
        try {
            BufferedWriter bwS;

            for (BufferedWriter bw : clients) {
                bwS = bw;
                if (!(bwSaida == bwS)) {
                    bw.write(name + " -> " + msg + "\r\n");
                    bw.flush();
                }
            }
        } catch (IOException e3) {
            Logger.getLogger(Server.class.getName()).log(Level.SEVERE, null, e3);
        }
    }

    public static void main(String[] args) {
        try {
            JLabel lblMsg = new JLabel("Porta do Servidor: ");
            JTextField txtPort = new JTextField("12345");
            Object[] texts = { lblMsg, txtPort };
            JOptionPane.showMessageDialog(null, texts);
            server = new ServerSocket(Integer.parseInt(txtPort.getText()));
            clients = new ArrayList<BufferedWriter>();
            JOptionPane.showMessageDialog(null, "Servidor ativo na porta: " + txtPort.getText());

            while (true) {
                System.out.println("Aguradando conexão...");
                Socket client = server.accept();
                System.out.println("Cliente conectado...");
                Thread t = new Server(client);
                t.start();
            }
        } catch (Exception e4) {
            Logger.getLogger(Server.class.getName()).log(Level.SEVERE, null, e4);
        }
    }
}