🎯 Online Quiz System - Multi-Client Real-Time Quiz Game

A comprehensive network programming project demonstrating 5 key Java networking concepts through an interactive quiz application.

📋 Project Overview

This project implements a real-time, multi-client quiz system where multiple players can connect to a central server, answer questions simultaneously, and compete for the highest score. The system demonstrates practical implementation of essential network programming concepts.

🎓 Network Programming Concepts Demonstrated

1. TCP Socket Programming

• Implementation: QuizServer.java, QuizClient.java
• Description: Establishes reliable, connection-oriented communication between server and clients
• Usage: Main communication channel for quiz questions and answers

2. Multithreading

• Implementation: ClientHandler.java, Thread pool in QuizServer.java
• Description: Handles multiple client connections concurrently using separate threads
• Usage: Each client connection runs in its own thread, allowing simultaneous player participation

3. Synchronization

• Implementation: QuizService.java, synchronized methods and blocks
• Description: Thread-safe management of shared resources (player scores, quiz state)
• Usage: Prevents race conditions when multiple threads update player scores

4. UDP Broadcasting

• Implementation: UDPBroadcaster.java, UDPResultsListener.java
• Description: Connectionless broadcasting of final results to all clients
• Usage: Broadcasts final leaderboard to all clients on the network

5. Client-Server Communication

• Implementation: Throughout the application
• Description: Bidirectional message exchange using JSON protocol
• Usage: Structured communication for quiz flow, questions, answers, and results

🏗️ Architecture

┌─────────────────────────────────────────────────────────┐
│                    Quiz Server                          │
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐ │
│  │ TCP Socket   │  │ Thread Pool  │  │ UDP Socket   │ │
│  │ (Port 5000)  │  │ (Max 10)     │  │ (Port 5001)  │ │
│  └──────────────┘  └──────────────┘  └──────────────┘ │
└─────────────────────────────────────────────────────────┘
                         │
        ┌────────────────┼────────────────┐
        │                │                │
   ┌────▼────┐      ┌────▼────┐     ┌────▼────┐
   │ Client 1│      │ Client 2│     │ Client 3│
   │(TCP+UDP)│      │(TCP+UDP)│     │(TCP+UDP)│
   └─────────┘      └─────────┘     └─────────┘

🚀 Getting Started

Prerequisites

• Java: JDK 17 or higher
• Maven: 3.6 or higher
• IDE: IntelliJ IDEA, Eclipse, or VS Code (optional)

Installation & Setup

1. Clone or Download the Project

   cd "e:\MCQ spring"

2. Build the Project

   mvn clean install

3. Start the Server

   mvn spring-boot:run

   The server will start on:

   • HTTP Server: http://localhost:8080
   • TCP Socket: Port 5000
   • UDP Socket: Port 5001

4. Access Web Interface

   • Open browser: http://localhost:8080
   • View server status and leaderboard

5. Run Client Application (Open multiple terminals for multiple clients)

   java -cp target/online-quiz-system-1.0.0.jar com.quiz.client.QuizClient

🎮 How to Play

1. Start the Server: Run the Spring Boot application
2. Connect Clients: Run the client application (minimum 2 clients required)
3. Enter Name: Each client enters their player name
4. Wait for Players: Server waits for at least 2 players before starting
5. Answer Questions: Players answer 5 multiple-choice questions
6. View Results: Final results are displayed via TCP and broadcast via UDP

📁 Project Structure

MCQ spring/
├── src/
│   └── main/
│       ├── java/com/quiz/
│       │   ├── QuizApplication.java          # Spring Boot main class
│       │   ├── model/
│       │   │   ├── Question.java             # Question model
│       │   │   ├── Player.java               # Player model
│       │   │   └── QuizMessage.java          # Message protocol
│       │   ├── service/
│       │   │   └── QuizService.java          # Quiz logic & synchronization
│       │   ├── server/
│       │   │   ├── QuizServer.java           # TCP server & multithreading
│       │   │   ├── ClientHandler.java        # Thread per client
│       │   │   └── UDPBroadcaster.java       # UDP broadcasting
│       │   ├── client/
│       │   │   ├── QuizClient.java           # Client application
│       │   │   └── UDPResultsListener.java   # UDP receiver
│       │   └── controller/
│       │       └── QuizController.java       # REST API endpoints
│       └── resources/
│           ├── application.properties        # Configuration
│           └── static/
│               ├── index.html                # Web UI
│               ├── styles.css                # Styling
│               └── script.js                 # Frontend logic
├── pom.xml                                   # Maven configuration
└── README.md                                 # This file

🔧 Configuration

Edit src/main/resources/application.properties:

# Server Configuration
server.port=8080
quiz.server.tcp.port=5000
quiz.server.udp.port=5001
quiz.server.max.clients=10

📊 Features

Server Features

• ✅ Accept multiple client connections (TCP)
• ✅ Handle clients concurrently (Multithreading)
• ✅ Manage quiz flow and questions
• ✅ Track player scores safely (Synchronization)
• ✅ Broadcast final results (UDP)
• ✅ Web-based monitoring dashboard
• ✅ REST API for status and leaderboard

Client Features

• ✅ Connect to server via TCP socket
• ✅ Real-time question receiving
• ✅ Interactive answer submission
• ✅ Score tracking
• ✅ UDP broadcast reception
• ✅ Console-based UI

🧪 Testing the Application

Test Scenario 1: Basic Quiz Flow

1. Start server
2. Connect 2 clients
3. Both clients enter names
4. Server starts quiz automatically
5. Clients answer all questions
6. View final results

Test Scenario 2: Multiple Clients

1. Start server
2. Connect 5+ clients simultaneously
3. Verify all clients receive questions
4. Check synchronization of scores
5. Confirm UDP broadcast reaches all

Test Scenario 3: Network Concepts

• TCP: Monitor connection establishment and data transfer
• Multithreading: Check server logs for thread creation
• Synchronization: Verify score consistency across threads
• UDP: Confirm broadcast reception on all clients
• Client-Server: Observe bidirectional message flow

👥 Group Members & Roles

Member	Role	Concept	Implementation
Member 1	Server Developer	TCP Socket	QuizServer.java
Member 2	Manager	Multithreading	ClientHandler.java
Member 3	Client Developer	Client-Server	QuizClient.java
Member 4	Score Manager	Synchronization	QuizService.java
Member 5	Broadcaster	UDP Datagram	UDPBroadcaster.java

📝 Example Console Output

Server Console:

===========================================
Quiz Server Started on Port: 5000
Waiting for clients to connect...
===========================================
Player joined: Alice (uuid-1234)
Player joined: Bob (uuid-5678)
Starting quiz with 2 players
===========================================
Quiz Started!
===========================================
Question 1: What is 2 + 2?
--- Current Scores ---
1. Alice - 10 points
2. Bob - 0 points
...

Client Console:

===========================================
  ONLINE QUIZ SYSTEM - CLIENT
===========================================
Connected to Quiz Server!
Enter your name: Alice
Waiting for other players... (2 players connected)

===========================================
Question 1 of 5
===========================================
What is 2 + 2?
1. 3
2. 4
3. 5
4. 6
Your answer (1-4): 2
Correct!
Your current score: 10 points

🐛 Troubleshooting

Server won't start

• Check if ports 5000, 5001, 8080 are available
• Verify Java 17+ is installed
• Run mvn clean install again

Client can't connect

• Ensure server is running
• Check firewall settings
• Verify SERVER_HOST and SERVER_PORT in QuizClient.java

UDP broadcast not received

• Check network configuration
• Verify UDP port 5001 is open
• Try using localhost for testing

🔒 Security Notes

This is an educational project. For production use, consider:

• Input validation and sanitization
• Authentication and authorization
• Encrypted communication (TLS/SSL)
• Rate limiting
• SQL injection prevention (if using database)

📚 Learning Resources

• Java Socket Programming
• Java Multithreading
• Spring Boot Documentation
• UDP vs TCP

📄 License

This project is created for educational purposes as part of a Network Programming course.

🤝 Contributing

This is a group project. All team members contribute to different modules as per their assigned roles.

📧 Support

For questions or issues, please contact your course instructor or teaching assistant.

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