Socket Programming Workshop

Welcome to the Java Socket Programming & IO Workshop! In this hands-on session, you'll explore practical examples using core Java concepts such as sockets, streams, buffering, and object serialization. You'll implement real-time communication, understand IO efficiency, and work with object data transfer between clients and servers.

🗂️ Project Structure

This workshop includes the following examples:

1. Group Chat (Multi-Client Chatroom)

2. Buffered vs Unbuffered IO Comparison

3. Object Stream Communication

4. 🧠 Final Assignment: Account Manager (with TODOs)

Each project is organized in its own package and highlights key Java concepts.

1. 💬 Group Chat

A multi-client chat application using Java sockets and multi-threading. It allows multiple clients to connect to a server and chat with each other in real-time.

🔧 Technologies Used

• Java Sockets (ServerSocket, Socket)

• Data Streams (DataInputStream, DataOutputStream)

• Multi-threading

📁 Files

• Server.java: Manages client connections and broadcasts messages.

• ClientHandler.java: Handles communication with each client in a separate thread.

• Client.java: Connects to the server and sends/receives messages.

Type messages in the client terminal to broadcast to all connected clients. (Type /quit to leave the chat.)

✅ Concepts Covered

• ServerSocket, Socket

• Multi-threaded server (each client handled in a thread)

• DataInputStream, DataOutputStream

• Real-time communication and message broadcasting

2. ⚡ Buffered vs Unbuffered I/O

Benchmark comparing file copy performance using buffered and unbuffered streams.

✅ Concepts Covered

• FileInputStream vs BufferedInputStream

• Byte stream handling

• Performance measurement with System.nanoTime()

📁 Files

• Gen.java – Generates a test file (file.dat)

• FileCopyBenchmark.java – Measures copy speed with and without buffering

3. 🧳 Object Stream

A simple client-server system where Java objects are sent over the network.

✅ Concepts Covered

• ObjectOutputStream, ObjectInputStream

• Serializable objects

• Transmitting full Java objects

📁 Files

• Person.java

• Server.java

• Client.java

4. 🧠 Account Manager

Design a client-server system to manage user sign-up and login with serialization and proper account storage.

🏗️ What’s Provided

• Serializable Account class

• Pre-built Client.java UI with input prompts

• Multithreaded Server.java setup

• Socket + object stream connections

✅ Your Tasks

• Hash the Password: Use a hashing algorithm (e.g., SHA-256) to store passwords securely. Replace the "HASHED_PASSWORD" placeholder.

• Sign-up Logic

• Serialize and send the Account object from client to server.

• Store new accounts on the server in a list or file.

• Login Logic: Validate the credentials against stored accounts on the server and Return success/failure message to the client.

• Handle Clients in handleClient()

• Implement server-side request handling based on client choice.

🧪 Bonus

• Prevent duplicate usernames

• Save/load accounts from disk or database

• Use JavaFX for UI

📁 Directory: Workshop.AccountManager

• Account.java

• Client.java (with input and TODOs)

• Server.java (with multithreaded handler and TODO)

🔁 Example Flow

--- Account Manager ---
1. Sign up
2. Log in
3. Exit