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.

Chess game demo built with JSocket

• 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

# 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)

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();
    }
}

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

• 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

For more detailed information:

• how it works - Detailed description of classes and methods

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

JSocket is MIT licensed.

Report Bug • Request Feature

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