📚 Library Management System A Java-based Library Management System developed as a Data Structures and Algorithms (DSA) project. It is a menu-driven console application for managing books, members, borrowing, returns, overdue books, borrowing history, and waitlists.
🎯 Project Overview The project demonstrates the practical use of:
Custom Singly Linked List
HashMap
ArrayList
Queue
Java Stream API
Custom Exceptions
Object-Oriented Programming
The main DSA requirement is a custom Singly Linked List for borrowing history.
✨ Features Option Feature Description
1 Add Book Add a new book with ID, title, author, and copies
2 Remove Book Remove a book from the catalog
3 Search by Title Case-insensitive title search using Stream API
4 Search by Author Case-insensitive author search
5 Issue Book Issue an available book or place the member in the waitlist
6 Return Book Return a book and process the waitlist when applicable
7 Overdue Books Display active books borrowed for more than 14 days
8 Display All Books Display the complete book catalog
9 Display All Members Display registered members and current borrowing details
10 View Borrowing History Display a member's history newest-first
0 Exit Exit the application 🧠 Data Structures Used
- Custom Singly Linked List Files: BorrowRecord.java, BorrowingHistory.java
BorrowRecord is the node containing:
Book ID
Book title
Issue date
Reference to the next node
New records are inserted at the head, so borrowing history is displayed newest to oldest.
HEAD ↓ Latest Borrow ↓ Previous Borrow ↓ Older Borrow ↓ NULL The borrowing history does not use java.util.LinkedList.
- HashMap File: Library.java
Book ID → Book Object Member ID → Member Object Book ID → Waitlist Queue Average ID lookup is O(1).
- ArrayList Files: Member.java, Library.java
Used for:
Currently borrowed book IDs
Search results
Dynamic collection handling
- Queue File: Library.java
Used for book waitlists.
The queue follows FIFO (First In, First Out), so the first waiting member is considered first.
🌊 Stream API The project uses Java Stream API in Library.java → searchByTitle().
The title search uses:
stream()
filter()
forEach()
toLowerCase()
contains()
Matching books are stored in an ArrayList.
Example:
catalog.values().stream()
.filter(book -> book.title.toLowerCase()
.contains(keyword.toLowerCase()))
.forEach(results::add);
Exception Purpose
BookNotFoundException Invalid or missing book ID
MemberNotFoundException Invalid or missing member ID
Main.java catches these exceptions and displays readable error messages.
📏 Important Rules Maximum Books Per Member A member can have a maximum of 3 books at a time.
Current Books < 3 ↓ Can Issue Waitlist If all copies are unavailable, a member can be added to the book's FIFO waitlist.
Overdue Books A book is overdue when it has been borrowed for more than 14 days.
The current project uses the fixed date:
Today = 2025-01-15 This fixed date makes overdue testing predictable and follows the project requirement.
📁 Project Structure LibraryManagementSystem/ │ ├── src/ │ ├── Book.java │ ├── BorrowRecord.java │ ├── BorrowingHistory.java │ ├── Member.java │ ├── Library.java │ ├── Main.java │ ├── BookNotFoundException.java │ ├── MemberNotFoundException.java │ └── BorrowLimitExceededException.java │ ├── .gitignore └── LibraryManagementSystem.iml File Responsibilities File Purpose
Book.java Stores book information and copy availability
BorrowRecord.java Represents a node in the custom linked list
BorrowingHistory.java Implements the custom singly linked list
Member.java Stores member details, current borrowing and history
Library.java Contains core library operations and data structures
Main.java Console menu, input handling and exception handling
BookNotFoundException.java Custom book-not-found exception
MemberNotFoundException.java Custom member-not-found exception
BorrowLimitExceededException.java Custom 3-book-limit exception 📦 Sample Data Books Book ID Title Author Copies
B001 Data Structures Mark Allen 2 B002 Clean Code Robert Martin 1 B003 Java Programming Herbert Schildt 3
Members Member ID Name
M001 Alice M002 Bob M003 Charlie
IntelliJ IDEA or another Java IDE
Git (optional)
IntelliJ IDEA Open the LibraryManagementSystem project.
Make sure JDK 17.0.6 is selected.
Open src/Main.java.
Run Main.java.
Use the console menu.
Terminal If the Java files are in the same directory:
javac *.java java Main 🖥️ Example Usage Issue a Book Enter choice: 5
Book ID: B001 Member ID: M001
→ Book issued successfully Borrowing History Enter choice: 10
Member ID: M001
Borrowing History:
- Java Programming
- Clean Code
- Data Structures The newest record appears first because new nodes are inserted at the head.
Waitlist Book: Clean Code Available Copies: 0
Member M002 requests the book.
→ M002 added to waitlist. When the book is returned, the next waiting member can receive the available copy.
🔄 Basic System Flow ┌──────────────┐ │ Main.java │ └──────┬───────┘ ↓ User selects option ↓ ┌──────────────┐ │ Library.java │ └──────┬───────┘ ↓ ┌──────────────┼──────────────┐ ↓ ↓ ↓ Books Members Waitlists HashMap HashMap Queue ↓ Borrowing History ↓ Custom Linked List 📊 Complexity Overview Operation Data Structure Complexity
Find Book by ID HashMap O(1) average Find Member by ID HashMap O(1) average Add History Record Singly Linked List O(1) Display History Singly Linked List O(n) Add to Waitlist Queue O(1) Remove from Waitlist Queue O(1) Search Books Stream / collection traversal O(n)
🧪 Testing The following scenarios are included:
Add a new book
Remove a book
Search by title
Search by author
Search with no matching result
Issue an available book
Return a book
Issue three books to one member
Attempt to issue a fourth book
Handle an invalid book ID
Handle an invalid member ID
Add a member to a waitlist
Return a book with a waiting member
Display borrowing history
Check overdue books
Display all books
Display all members
Tests Already Performed The project has been run successfully from IntelliJ.
Key cases already tested include:
Title search with no matching result
Invalid book ID handling
The 3-book borrowing limit
Custom exception output
Remaining demonstration cases should be captured as screenshots for the final report.
🎓 DSA Concepts Demonstrated Singly Linked List
Nodes and references
Head pointer
HashMap
ArrayList
Queue
FIFO
Searching
Insertion
Deletion
Traversal
Stream API
Exception handling
Time complexity
Object-oriented programming
🚀 Future Improvements Possible enhancements:
GUI
Database integration
Login and authentication
Book reservation system
Fine calculation
Persistent data storage
Advanced search and filtering
Admin and member roles
👨💻 Technologies Used Java 17.0.6
IntelliJ IDEA
Git / GitHub
Object-Oriented Programming
Data Structures & Algorithms
HashMap
ArrayList
Queue
Custom Singly Linked List
Java Stream API
LocalDate
Custom Exceptions
📌 Project Status The project was rebuilt as a fresh IntelliJ IDEA project using Java 17.0.6.
Current status:
✅ Java source files implemented
✅ DSA structures implemented
✅ Stream API implemented
✅ Three custom exceptions implemented
✅ Application run successfully
✅ Key test cases performed
✅ Project pushed to GitHub master branch
⏳ Final screenshots pending
⏳ Final printed report pending
📄 License This project is intended for educational and academic purposes.