├── README.md
└── ChatServer.java


/README.md:
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1 | # java-chat-app
2 | A simple command-line chat application in Java.
3 | 


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/ChatServer.java:
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 1 | import java.io.*;
 2 | import java.net.*;
 3 | import java.util.*;
 4 | 
 5 | public class ChatServer {
 6 |     private static Set<PrintWriter> clientWriters = new HashSet<>();
 7 | 
 8 |     public static void main(String[] args) throws Exception {
 9 |         System.out.println("Chat server started...");
10 |         ServerSocket serverSocket = new ServerSocket(12345);
11 |         while (true) {
12 |             new ClientHandler(serverSocket.accept()).start();
13 |         }
14 |     }
15 | 
16 |     private static class ClientHandler extends Thread {
17 |         private Socket socket;
18 |         private PrintWriter out;
19 |         private BufferedReader in;
20 | 
21 |         public ClientHandler(Socket socket) {
22 |             this.socket = socket;
23 |         }
24 | 
25 |         public void run() {
26 |             try {
27 |                 in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
28 |                 out = new PrintWriter(socket.getOutputStream(), true);
29 |                 synchronized (clientWriters) {
30 |                     clientWriters.add(out);
31 |                 }
32 | 
33 |                 String message;
34 |                 while ((message = in.readLine()) != null) {
35 |                     System.out.println("Received: " + message);
36 |                     for (PrintWriter writer : clientWriters) {
37 |                         writer.println(message);
38 |                     }
39 |                 }
40 |             } catch (IOException e) {
41 |                 System.out.println(e.getMessage());
42 |             } finally {
43 |                 try {
44 |                     socket.close();
45 |                 } catch (IOException e) {
46 |                     System.out.println(e.getMessage());
47 |                 }
48 |                 synchronized (clientWriters) {
49 |                     clientWriters.remove(out);
50 |                 }
51 |             }
52 |         }
53 |     }
54 | }
55 | 


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