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Spring Boot Tutorial

Build production-style Java web services: starters, REST, Spring Data JPA, profiles, tests and Actuator

Intermediate4 lessonsabout 21 min of reading

This course is for developers who already know core Java (classes, collections, interfaces, exceptions) and want to build the kind of backend service that job descriptions mean when they say Spring Boot. If you are not comfortable with those yet, work through the Java course first. You do not need any prior Spring experience.

Across four lessons you will understand what a starter and auto-configuration really are, build a validated REST endpoint with DTOs and consistent error responses, store data with Spring Data JPA while avoiding the N+1 query trap, and finish with externalised configuration, profiles, slice tests and Actuator health checks. Each lesson uses its own small domain (a parcel-locker kiosk, a clinic booking desk, a bike-share network, a metro fare engine) so the ideas stay separate in your head.

A note on accuracy: the snippets target Spring Boot 3.x (Java 17 or newer, jakarta.* packages). They use long-stable annotations and APIs, but I could not execute Spring in the environment this course was written in, so response bodies are shown only where they follow directly from the code. Where behaviour changed between 3.x minor versions, the lesson says so. Plain-Java snippets with printed output were compiled and run.

Start lesson 1: Spring Boot SetupRide it: tricks, quizzes, XP

Spring Boot lessons

  1. 1Spring Boot Setup: Starters, Auto-Configuration and Your First AppSet up a Spring Boot 3 project, learn what starters and auto-configuration really do, and override a default bean with @ConditionalOnMissingBean.5 min read
  2. 2Spring Boot REST Controllers, DTOs and ValidationBuild a Spring Boot REST API with controllers, record DTOs, Bean Validation and a central @RestControllerAdvice that returns clean 400, 404 and 409 errors.6 min read
  3. 3Spring Data JPA with Spring Boot: Repositories and the N+1 ProblemUse Spring Data JPA in Spring Boot: map entities, write derived query methods, then find and fix the N+1 select problem with fetch joins and entity graphs.5 min read
  4. 4Spring Boot Profiles, Configuration, Testing and ActuatorExternalise Spring Boot configuration with @ConfigurationProperties and profiles, write unit and @WebMvcTest tests, and expose health checks with Actuator.5 min read

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