Car Rental Management System

A console-based Car Rental Management System built in Java using Object-Oriented Programming (OOP) principles.

Features

• Vehicle Management — Add, view, search, update, delete vehicles; mark as rented or available
• Customer Management — Register and manage customer records with license tracking
• Booking Management — Create bookings with date validation and overlap detection
• Rental Management — Start/end rentals, calculate charges, track additional fees
• File Persistence — All data is saved to .txt files and reloaded on startup
• Authentication — Login system with attempt limiting

OOP Concepts Used

Concept	Where
Abstract Class	AbstractEntity — base class for all entities
Inheritance	Vehicle, Customer, Booking, Rental all extend AbstractEntity
Encapsulation	Private fields with getters/setters in every class
Polymorphism	displayMenu(), add(), viewAll() etc. overridden per class
Static members	Shared in-memory lists (vehicles, customers, etc.)

Project Structure

├── AbstractEntity.java     # Abstract base class
├── Vehicle.java            # Vehicle entity and management
├── Customer.java           # Customer entity and management
├── Booking.java            # Booking entity and management
├── Rental.java             # Rental entity and management
└── CarRentalSystem.java    # Main entry point

How to Run

Prerequisites

• Java JDK 17 or higher

Compile

javac \\\*.java

Run

java CarRentalSystem

Login

Username: admin
Password: pass123

Data Storage

The system automatically creates the following files on first run to persist data between sessions:

• vehicles.txt
• customers.txt
• bookings.txt
• rentals.txt

Author

Developed as part of a 3rd year Computer Science OOP course project.

## Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

## License

This project is for educational purposes as part of a 3rd year Computer Science OOP course.

## Sample Data

On first run the system auto-creates these data files:

- vehicles.txt — stores all vehicle records

- customers.txt — stores all customer records

- bookings.txt — stores all booking records

- rentals.txt — stores all rental records

OOP Design Decisions

• AbstractEntity enforces a contract all entities must follow via abstract methods
• Each entity manages its own file I/O through loadFromFile() and saveToFile()
• Static lists act as in-memory storage shared across the application
• Scanner is shared via AbstractEntity to avoid multiple open input streams

Future Improvements

• Add password hashing for secure authentication
• Implement invoice/receipt generation
• Add vehicle category filtering
• Support multiple admin users
• Export reports to CSV