Spring Boot Social Media REST APIs

A Spring Boot REST API project for a social media application demonstrating core backend development concepts and best practices. Built as a learning reference covering RESTful design, JPA/Hibernate, exception handling, API versioning, Swagger documentation, and more.

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Tech Stack

Layer	Technology
Framework	Spring Boot 2.4.5
Language	Java 11
Build Tool	Maven
Database	H2 (in-memory)
ORM	Spring Data JPA / Hibernate
API Docs	Springfox Swagger 3.0
Monitoring	Spring Boot Actuator
REST Extras	HATEOAS, HAL Explorer
Validation	Spring Boot Validation

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Project Structure

myNewProject/
├── pom.xml
└── src/
    └── main/
        ├── java/com/mynewproject/myNewProject/
        │   ├── MyNewProjectApplication.java       # App entry point + i18n config
        │   ├── SwaggerConfig.java                 # Swagger/OpenAPI configuration
        │   │
        │   ├── user/                              # Core social media feature
        │   │   ├── User.java                      # JPA entity
        │   │   ├── Post.java                      # JPA entity
        │   │   ├── UserRepository.java            # Spring Data JPA repository
        │   │   ├── PostRepository.java            # Spring Data JPA repository
        │   │   ├── UserDaoService.java            # In-memory DAO (demo purposes)
        │   │   ├── UserNotFoundException.java     # Custom 404 exception
        │   │   ├── UserReources.java              # REST controller (in-memory DAO)
        │   │   └── UserJPAResources.java          # REST controller (JPA/database)
        │   │
        │   ├── exception/                         # Global exception handling
        │   │   ├── CustomisedResponseEntityExceptionHandler.java
        │   │   └── ExceptionResponse.java
        │   │
        │   ├── helloWorld/                        # Basic Spring REST examples + i18n
        │   │   ├── HelloWorldController.java
        │   │   └── HelloBoy.java
        │   │
        │   └── versioning/                        # API versioning strategies demo
        │       ├── PersonVersionController.java
        │       ├── PersonV1.java
        │       ├── Personv2.java
        │       └── Name.java
        │
        └── resources/
            ├── application.properties
            ├── data.sql                           # H2 seed data
            ├── messages.properties                # English (default)
            ├── messages_fr.properties             # French
            └── messages_hi.properties             # Hindi

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API Endpoints

Social Media — In-Memory DAO

Method	Endpoint	Description
GET	/users	Get all users
GET	/users/{id}	Get user by ID (with HATEOAS links)
POST	/users	Create a new user
DELETE	/users/{id}	Delete a user

Social Media — JPA / Database

Method	Endpoint	Description
GET	/JPA/users	Get all users
GET	/JPA/users/{id}	Get user by ID
POST	/JPA/users	Create a new user
DELETE	/JPA/users/{id}	Delete a user
GET	/JPA/users/{id}/posts	Get all posts by a user
POST	/JPA/users/{id}/posts	Create a post for a user

Hello World / Basics

Method	Endpoint	Description
GET	/hello-world	Basic hello world
GET	/hello-boy	Returns JSON object
GET	/hello-boy/pathvariable/{name}	Path variable demo
GET	/hello-boy-internationalised	i18n demo (set Accept-Language header)

API Versioning Demo

Method	Endpoint	Description
GET	/v1/person	URI versioning — v1
GET	/v2/person	URI versioning — v2
GET	/person/param?version=1	Request param versioning
GET	/person/param?version=2	Request param versioning
GET	/person/header	Header versioning (X-API-VERSION: 1 or 2)
GET	/person/produces	Content negotiation versioning (Accept header)

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Running the Project

Prerequisites: Java 11+, Maven 3.6+

cd myNewProject
./mvnw spring-boot:run

The app starts on http://localhost:8080

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Useful URLs

URL	Description
http://localhost:8080/swagger-ui.html	Swagger API documentation UI
http://localhost:8080/v2/api-docs	Swagger JSON spec
http://localhost:8080/actuator	All actuator endpoints
http://localhost:8080/h2-console	H2 database console
http://localhost:8080/browser	HAL Explorer

H2 Console settings: JDBC URL jdbc:h2:mem:testdb, no password needed.

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Database

Uses H2 in-memory database seeded via data.sql on startup:

• 3 Users: Hardik, Hitesh, Mayank
• 3 Posts: 2 by Hardik, 1 by Mayank

Schema is auto-generated by Hibernate from JPA entities.

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Key Concepts Demonstrated

• RESTful API design — GET, POST, DELETE with proper HTTP status codes
• JPA / Hibernate — Entity mapping, repositories, relationships (One-to-Many)
• Exception handling — Global @ControllerAdvice with custom error responses
• HATEOAS — Hypermedia links in API responses
• API Versioning — URI, request param, header, and content negotiation strategies
• Internationalization (i18n) — Accept-Language header support (EN, FR, HI)
• Validation — Bean validation (@Size, @Past) with error responses
• Swagger — Auto-generated interactive API documentation
• Actuator — Application health and metrics endpoints

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Security Note

Default credentials in application.properties (hardik / 12345678) are for local development only. Never commit real credentials to source control.