ChatServer2.java

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

public class ChatServer2 {
    private static final int PORT = 5000;
    private static Set<ClientHandler> clientHandlers = new HashSet<>();

    public static void main(String[] args) {
        try (ServerSocket serverSocket = new ServerSocket(PORT)) {
            System.out.println("Chat server started...");

            while (true) {
                Socket clientSocket = serverSocket.accept();
                ClientHandler clientHandler = new ClientHandler(clientSocket);
                clientHandlers.add(clientHandler);
                new Thread(clientHandler).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    // Broadcast message to all clients
    private static synchronized void broadcast(String message, ClientHandler sender) {
        for (ClientHandler client : clientHandlers) {
            if (client != sender) {
                client.sendMessage(message);
            }
        }
    }

    // Remove a client from the active list
    private static synchronized void removeClient(ClientHandler clientHandler) {
        clientHandlers.remove(clientHandler);
    }

    static class ClientHandler implements Runnable {
        private Socket socket;
        private PrintWriter out;
        private BufferedReader in;
        private boolean active = true;

        public ClientHandler(Socket socket) {
            this.socket = socket;
        }

        @Override
        public void run() {
            try {
                in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                out = new PrintWriter(socket.getOutputStream(), true);
                System.out.println("New client connected: " + socket);

                String message;
                while (active && (message = in.readLine()) != null) {
                    System.out.println("Received: " + message);
                    if (message.equalsIgnoreCase("bye")) {
                        active = false;
                        out.println("bye"); // Send goodbye to client
                        break;
                    }
                    broadcast(message, this);
                }
            } catch (IOException e) {
                System.out.println("Client disconnected.");
            } finally {
                closeResources();
            }
        }

        public void sendMessage(String message) {
            out.println(message);
        }

        private void closeResources() {
            try {
                if (out != null) out.close();
                if (in != null) in.close();
                if (socket != null) socket.close();
                removeClient(this);
                System.out.println("Client connection closed.");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}