spring-boot-task-api

A small but complete REST API built with Spring Boot, demonstrating a standard CRUD service with database persistence and request validation. Built as a learning project to practise the Spring ecosystem (Spring MVC, Spring Data JPA, Hibernate).

Tech stack

• Java 17
• Spring Boot 3.3 (Spring Web, Spring Data JPA, Validation)
• Hibernate (JPA)
• H2 in-memory database (easily swappable for PostgreSQL)
• Maven

API

A CRUD REST API over a Task resource:

Method	Route	Description
GET	/tasks	List all tasks
GET	/tasks/{id}	Get a single task (404 if not found)
POST	/tasks	Create a task (validates input)
PUT	/tasks/{id}	Update a task
DELETE	/tasks/{id}	Delete a task (404 if not found)

A Task has a title (required, max 200 chars), an optional description, and a done flag. Invalid input — such as an empty title — is rejected with 400 Bad Request.

Running locally

Requires a JDK (17+) and Maven.

mvn spring-boot:run

The API starts on http://localhost:8080. Alternatively, open the project in IntelliJ IDEA and run TasksApplication.

The database is H2 in-memory, created on startup and discarded on shutdown — no setup required. You can browse it at http://localhost:8080/h2-console (JDBC URL jdbc:h2:mem:tasksdb, user sa, empty password).

Example requests

# Create a task
curl -X POST http://localhost:8080/tasks \
  -H "Content-Type: application/json" \
  -d '{"title":"Write documentation","description":"Cover all endpoints"}'

# List tasks
curl http://localhost:8080/tasks

# Update a task
curl -X PUT http://localhost:8080/tasks/1 \
  -H "Content-Type: application/json" \
  -d '{"title":"Write documentation","done":true}'

# Delete a task
curl -X DELETE http://localhost:8080/tasks/1

Project structure

src/main/java/com/example/tasks/
├── TasksApplication.java          # entry point
├── model/Task.java                # JPA entity (maps to the task table)
├── repository/TaskRepository.java # Spring Data repository (DB access)
└── controller/TaskController.java # REST controller (the HTTP endpoints)

The layering follows the standard Spring pattern: the controller handles HTTP, the repository handles persistence, and the entity defines the data model. Database schema is generated from the entity by Hibernate.

Switching to PostgreSQL

The code is database-agnostic via JPA. To run against PostgreSQL instead of H2, swap the H2 dependency in pom.xml for the PostgreSQL driver and update the datasource settings in application.properties (a commented example is included there). No Java code changes are required.