A lightweight desktop chat application built in Java using UDP Multicasting. It enables users connected to the same Local Area Network (LAN) to send and receive messages in real-time. Built with NetBeans IDE, this project demonstrates core Java network programming using the User Datagram Protocol (UDP).
- 💬 Real-time text messaging over LAN
- 📡 Uses UDP Multicast to broadcast messages to all clients
- 🧑🤝🧑 Supports multiple users chatting simultaneously
- ⚡ Lightweight, no server needed
- 🧰 Simple GUI built with Java Swing
- 🖥️ Desktop application (cross-platform)
- 📦 Easily runnable in NetBeans IDE
- Java SE
- UDP (DatagramSocket & MulticastSocket)
- Swing (Java GUI Toolkit)
- NetBeans IDE
git clone https://github.com/mahamadayazmomin/lan-chat-app.git
- Open NetBeans IDE
- Go to File → Open Project
- Navigate to the cloned repository and open the project folder
- Clean and Build the project
- Run the ChatClient.java file (or appropriate main class)
🔁 Repeat this step on multiple computers connected to the same LAN to test chat functionality.
- Each client joins a Multicast Group (e.g., 230.0.0.0 on port 4446)
- When a message is sent, it is broadcast to all group members
- Each client listens to the same multicast address and displays the received messages in the GUI
- No central server is needed; the architecture is peer-to-peer
- Java 8 or above
- NetBeans IDE (any recent version)
- All clients must be connected to the same Local Network
- Only works within the same LAN
- Does not support file transfer or message encryption
- May not work if multicast is disabled on the router/network
- Add user authentication
- Implement message history
- Add file sharing capability
- Add emojis or formatting
- Use TCP for guaranteed delivery (optional variant)
This open-source project is available under the MIT License.
Inspired by the core concepts of Java Network Programming. Created as a simple educational project for learning UDP multicast in local networks.