Library Management System (Spring Boot)

A backend-focused Library Management System built with Spring Boot, showcasing REST API design, JWT-based authentication, Spring Security, and JPA/Hibernate with PostgreSQL.

This project is designed as a portfolio backend application, demonstrating real-world patterns such as layered architecture, DTO mapping, validation, and stateless authentication.

Features

Core Domain

• Manage Books, Authors, Categories
• Track Loans (borrow / return books)
• Prevent borrowing a book that is already loaned out
• Availability tracking per book

Authentication & Security

• JWT-based authentication
• Stateless API (no sessions)
• Spring Security filter chain with custom JWT filter
• In-memory users for demo purposes
• Protected endpoints with access control

API & Developer Experience

• RESTful endpoints
• DTO-based request/response models
• Bean Validation (@NotNull, @Size, etc.)
• Global exception handling
• Swagger / OpenAPI documentation
• Actuator health endpoint

Tech Stack

• Java 21
• Spring Boot 4
• Spring Web
• Spring Data JPA (Hibernate)
• Spring Security
• JWT (jjwt)
• PostgreSQL
• Swagger / OpenAPI (springdoc)
• Maven

Architecture Overview

controller  →  service  →  repository  →  database
     ↓            ↓
    DTOs       business rules