Learn Spring Boot 4

A two-day course on Spring Boot 4, built on Spring Framework 7. No Spring experience needed. Java basics are assumed — see Learn Java 25 if you need them first.

Everything here runs with a JDK and the Maven wrapper — no application server, no XML.

Why Spring Boot 4?

Spring Boot 4.0 (November 2025) sits on Spring Framework 7: a fully modularized code base, null safety with JSpecify, API versioning, declarative HTTP service clients and first-class Java 25 support — while keeping Java 17 as the baseline.

Course outline

IntroductionSetup · First app
Day 1beans, configuration, REST, validation, data, HTTP clients, tests
Day 2API versioning, null safety, security, actuator, resilience, threads, messaging, deployment
AppendixCheat sheet · Resources

Each chapter ends with ★ Exercises. Type the samples instead of pasting them — reading stack traces is how you learn Spring fastest.

What you need

  • A JDK 25 build (Temurin, Corretto, Oracle OpenJDK) — Java 17 also works
  • IntelliJ IDEA Community, or VS Code with the Spring Boot extension pack
  • A terminal — every sample runs with ./mvnw

Start with the setup →