JSocket: Lightweight Java WebSocket Server Development

Mohamed Dev

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Java

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JSocket 🚀

A lightweight, easy-to-understand Java WebSocket server for real-time applications

JSocket provides a simple yet powerful WebSocket implementation in Java with no external dependencies. Perfect for learning WebSocket internals, building custom real-time features, or integrating into existing Java applications.

Video Below is just an example of what the JSocket can do

✨ Features

Beginner-friendly code structure with extensive documentation

RFC 6455 compliant WebSocket implementation

Concurrent client handling with dedicated reader/writer threads

Event-driven architecture via simple listener interface

Working Chess game demo showcasing real-time capabilities

Zero external dependencies - just pure Java

🚀 Quick Start

Run the Chess Demo

# Clone the repository
git clone https://github.com/AceAtDev/JSocket--java-simple-websocket
cd JSocket

# Run the Chess server (using your IDE or command line)
java javaWebsocketChess.chess.ChessServerMain

# Open in browser: javaWebsocketChess/chess/clientApp/index.html
# (Open in two tabs to play against yourself)

Use JSocket in Your Project

1️⃣ Copy the core files from javaWebsocketChess/websocketCore/ into your project

2️⃣ Create your handler:

public class MyWebSocketHandler implements WebSocketListener {
    @Override
    public void onOpen(ClientHandler connection) {
        connection.sendMessage("Welcome!");
    }

    @Override
    public void onMessage(ClientHandler connection, String message) {
        System.out.println("Received: " + message);
        connection.sendMessage("You said: " + message);
    }

    @Override
    public void onClose(ClientHandler connection, int code, String reason, boolean remote) {
        System.out.println("Connection closed: " + reason);
    }

    @Override
    public void onError(ClientHandler connection, Exception ex) {
        ex.printStackTrace();
    }
}

3️⃣ Start the server:

public static void main(String[] args) {
    WebSocketServer server = new WebSocketServer(8888, new MyWebSocketHandler());
    try {
        server.start();
        System.out.println("WebSocket server running on port 8888");
    } catch (IOException e) {
        e.printStackTrace();
    }
}

🧩 Key Components

JSocket's architecture is simple but powerful:

WebSocketServer: Manages TCP connections and handshakes

ClientHandler: Manages WebSocket connection lifecycle

WebSocketDataReader/Writer: Handle frame reading/writing

WebSocketFrame: Represents WebSocket protocol frames

WebSocketListener: Interface for your application logic

🔍 Use Cases

Learning WebSocket internals without complex dependencies

Real-time chat applications

Multiplayer games (like the included Chess demo)

Live dashboards and monitoring tools

Adding WebSocket capability to existing Java applications

📚 Documentation

For more detailed information:

how it works - Detailed description of classes and methods

🤝 Contributing

Contributions are welcome! Whether it's bug reports, feature requests, or code contributions:

Fork the repository

Create your feature branch: git checkout -b feature/amazing-feature

Commit your changes: git commit -m 'Add some amazing feature'

Push to the branch: git push origin feature/amazing-feature

Open a Pull Request

📄 License

JSocket is MIT licensed.

Developed with ❤️ for the craft of developing

Report Bug • Request Feature

🙏 Acknowledgements

Special thanks to the amazing python-websockets/websockets project for their wonderful documentation, which was invaluable in creating this repository.

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Completed work

Posted Jul 18, 2025

Developed JSocket, a lightweight Java WebSocket server.

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