Library Management System (OOP) 📚

This repository contains the solution for Task 3: Library Management System.

Objective

The goal was to develop a mini Library Management System using Object-Oriented Programming (OOP) principles in Java, demonstrating class interaction and encapsulation. The system is designed to manage book records and handle the core transactions of issuing and returning books.

System Architecture (Classes)

The system is built upon three main classes:

1. Book.java: Represents a physical book with properties like title, author, isbn, and an internal status (isIssued).
2. User.java: Represents a library member with properties like userId and name. It also maintains a local list of issuedBooks.
3. Library.java: Acts as the central Controller. It holds ArrayList collections of all Book and User objects and contains the main business logic for issueBook() and returnBook().

Core Features

• Book Management: Allows adding new books and users.
• Encapsulation: Book and User details are managed through getters/setters, and the internal lists are managed by the Library class.
• Issue Logic:
  • Finds the book by ISBN and the user by ID.
  • Fails if the book is already issued, the user/book is not found.
  • Updates the book's status and adds the book to the user's issuedBooks list.
• Return Logic:
  • Reverses the issue process.
  • Removes the book from the user's issuedBooks list.
  • Sets the book's status back to isIssued = false.

How to Run

1. Ensure all four files (Book.java, User.java, Library.java, and Main.java) are in the same folder.
2. Compile the Java files:

   javac *.java

3. Run the main class:

   java Main