Hexagonal Architecture in Spring Boot — Win a Free Book

Source: Dev.to

We’re Running a Contest — Refactor to Hexagonal Architecture and Win a Book

I just published a full tutorial on Hexagonal Architecture in Spring Boot, and we’re running a contest alongside it.

The prize is “Get Your Hands Dirty on Clean Architecture” by Tom Hombergs as an ebook — the book that popularized this exact pattern in the Java world.

What the video covers

In Episode 1 of my Spring Boot series I showed a basic api/domain/infrastructure structure. This episode takes it further — proper Ports & Adapters, an explicit application layer, and the thing that makes it all worth it: business‑logic tests that run in 50 ms instead of 45 seconds.

The key insight the video builds toward: Spring’s dependency injection is already the hexagonal mechanism. When your controller injects RegisterUser and Spring provides RegisterUserService — that is ports and adapters. You just need to be intentional about which interfaces go where.

→ Watch the full episode on YouTube

The contest

1. Fork the repo.
2. Refactor the user and order packages to Hexagonal Architecture.
3. Open a Merge Request and drop the link in the YouTube comments.

A valid submission must meet all of the following:

• Ports use business‑oriented names (e.g., loadUser instead of findById).
• The domain package contains zero Spring annotations.
• At least one test runs without @SpringBootTest.

One random winner from all valid submissions receives the ebook.

Deadline

02 April 2026

Repository

GitLab – Hexagonal Architecture branch

Part of an ongoing Spring Boot + DDD series. Next up: Value Objects.