📚 Library Management System - Java OOP Project

🎯 Objective

A simple object-oriented Library Management System built using Java.
This mini project helps manage books and users, with features to issue and return books using core OOP principles.

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🧩 Project Structure

LibraryManagement/
├── Book.java
├── User.java
├── Library.java
├── Main.java
└── README.md

📘 Book.java

Represents a book in the library.

• Fields:
  id, title, author, isIssued
• Methods:
  getId(), getTitle(), getAuthor(), isIssued()
issue(), returnBook()
toString() for formatted display

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👤 User.java

Represents a user who can issue a book.

• Fields:
  userId, name, issuedBook
• Methods:
  getUserId(), getName(), getIssuedBook()
issueBook(Book), returnBook()
toString() for user display

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🏢 Library.java

Manages all books and users.

• Fields:
  List<Book> books, List<User> users
• Methods:
  addBook(Book), addUser(User)
findBookById(String), findUserById(String)
issueBook(String bookId, String userId)
returnBook(String userId)
listAllBooks(), listAllUsers()

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🚀 Main.java

The entry point of the application.

• Adds sample books and users.
• Demonstrates the issue and return functionality with console outputs.

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🧠 OOP Concepts Demonstrated

| OOP Concept | Implementation Description |

|------------------------ |------------------------------------------------------ |

| Encapsulation | Fields are private; access through getters/setters |

| Abstraction | Library class hides internal logic behind public methods |

| Composition | Library has Book and User; User has Book |

| Polymorphism | toString() overridden for custom output |

| Constructor Chaining | Used to initialize objects cleanly |

| Dynamic Binding | Resolved at runtime using overridden methods |

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🧪 How to Compile & Run

✅ Prerequisites

• Java JDK installed
• Text editor or IDE (e.g., Eclipse, VS Code)

▶️ Steps

javac *.java
java Main