📚 Library Management System (Java OOP)

📖 Overview

The Library Management System is a simple menu-driven console application built using Java Object-Oriented Programming (OOP) concepts. It allows users to add, remove, borrow, return, and display books in a library. The project demonstrates Encapsulation, Inheritance, Abstraction, and Polymorphism in a real-world example.

✨ Features

• ➕ Add a Book – Add new books with Title, Author, and ISBN.

• ➖ Remove a Book – Remove books from the library using ISBN.

• 📖 Borrow a Book – Borrow books if available.

• 🔄 Return a Book – Return borrowed books to the library.

• 📑 Display All Books – View all books with their availability status.

• 🚪 Exit System – Exit cleanly with a goodbye message.

🛠 OOP Concepts Used

1. Encapsulation –

   • Book details (title, author, ISBN, availability) are private with getters/setters.

   • User details (name, ID) are encapsulated.

2. Inheritance –
   • Student and Librarian classes inherit from abstract User class.
3. Abstraction –
   • Abstract class User defines displayInfo() method which is overridden.
4. Polymorphism –

   • Compile-time: Method overloading (setters, constructors).

   • Runtime: Method overriding (displayInfo() in Student & Librarian).

🏗 Project Structure

LibraryManagementSystem/
│
├── Book.java           # Book entity (Encapsulation)
├── User.java           # Abstract User class (Abstraction)
├── Student.java        # Student extends User (Inheritance + Polymorphism)
├── Librarian.java      # Librarian extends User (Inheritance + Polymorphism)
├── Library.java        # Manages list of books
└── Main.java           # Runs the menu-driven program 

▶️ How to Run

Using IntelliJ IDEA / Eclipse

• Open your IDE and create a Java Project.

• Copy all the .java files into the src folder.

• Set Main.java as the main class (contains public static void main).

• Run the project → The Library Management System menu will appear in the console.

📌 Example Usage

 Library Management System Menu:
1. Add Book
2. Remove Book
3. Borrow Book
4. Return Book
5. Display All Books
0. Exit
Enter your choice: 1
Enter Title: Java Basics
Enter Author: James Gosling
Enter ISBN: 101
✅ Book added successfully!

👨‍💻 Author

Lohar Sumermal
Java Developer | Backend Enthusiast