Java Messenger Application

Overview

This is a real-time, multi-user messaging application built in Java, featuring a client-server architecture that allows users to communicate through direct messages, group broadcasts, and file sharing.

System Architecture

The application consists of three main components:

1. Server (Server.java): Manages client connections, message routing, and system logging
2. ** Client Handler (ClientHandler.java)**: Manages individual client connections and message processing
3. Client (Client.java): Provides the user interface for sending and receiving messages

Key Features

Communication Modes

1. Broadcast Messaging

   • Send messages to all connected users
   • Real-time message distribution
   • Instant notification when users join or leave the server

2. Direct Messaging

   • Send private messages to specific users
   • Targeted communication without disturbing other users
   • Recipient-specific message routing

3. File Transfer

   • Send files directly to specific users
   • Supports various file types and sizes
   • User-friendly file selection and saving process

User Interface

• Clean, intuitive Swing-based graphical interface
• Resizable message area
• Color-coded buttons for different actions
• Username-based identification

Networking

• Localhost-based server connection
• Concurrent client handling
• Robust error management and connection handling

Technical Details

Server Capabilities

• Port 5000 for client connections
• Concurrent client management
• Server-side logging of events
• Client list management
• Timestamp tracking for connections and messages

Logging

• Comprehensive logging to server_logs.txt

• Tracks:

  • User connections
  • Disconnections
  • Direct messages
  • File transfers

User Workflow

1. Launch server application
2. Start client application
3. Enter unique username
4. Choose communication method:
   • Broadcast message
   • Direct message to specific user
   • Send file to specific user
   • List connected clients

Technical Implementation Highlights

• Java Swing for GUI
• Socket programming for network communication
• Multithreading for concurrent connections
• Stream-based file transfer
• Error handling and graceful disconnection

Potential Improvements

1. Encryption for message and file transfer
2. User authentication
3. Persistent message history
4. Support for multiple chat rooms
5. Enhanced file transfer with progress tracking

Technical Requirements

• Java Development Kit (JDK) 8 or higher
• No external libraries required beyond standard Java libraries

Security Considerations

• Currently operates on localhost
• No built-in encryption
• Recommended for local network or trusted environments

Code Structure

• Package: messenger.server for server-side components
• Package: messenger.client for client-side components
• Modular design allowing easy extension and modification

Limitations

• Single server instance
• No persistent user accounts
• Limited to text and file communication
• Localhost-only communication

Development and Deployment

1. Compile server and client classes
2. Start server application
3. Launch multiple client instances
4. Begin messaging

Sample Use Cases

• Local team communication
• Small office messaging
• Educational network programming demonstration
• Prototype for more advanced messaging systems

Licensing Open-source project for educational and personal use. Would you like me to elaborate on any specific aspect of the application? I can provide more technical details, explain the code structure, or discuss potential future enhancements.