Nowadays traditional layered monolithic architecture in Java world is not so popular as 5-10 years ago. I remember how we wrote tons of code for each layer repeating almost the same parts for every application. Add unit and integration testing to understand how much time and efforts has been spent on repeatable work. All cool ideas around DDD (domain driven design) and Hexagonal Architecture was just a nice theory because reality hasn’t allow us to implement it easily. Even Dependency Injection with Spring framework was completely focused on traditional layered approach, not even talking about JavaEE platform. Today we have Spring Boot ecosystem covering most of our needs for integration with almost all possible technologies and microservices architectural trend, enabling completely new approach to build Java applications around domain model. It is so natural to build Java domain-oriented services and connect them with external world using ports and adapters, that Hexagonal Architecture is almost enabled by default. You just need to switch your way of thinking…

1. Hexagonal architecture
with Spring Boot
Mikalai Alimenkou
@xpinjection
http://xpinjection.com

3. Telegram channel
https://t.me/xpinjection_channel

4. Disclaimer
This talk is based on
personal experience

5. Domain Driven Design
Expectations
Reality

6. Everything is simple!

8. Layered
architecture
must have layers

9. Layered architecture for kids

10. More serious view

11. Help Dasha to find business logic

12. Business logic is
easier to find
and understand
in single place

13. Everything should be Use Case driven

14. Alternative world

15. To connect to
the port you
need an adapter

16. Ports and adapters thinking

18. Fresh architectural paradigms

19. Spring Boot as game changer

20. Each service has similar structure
SERVICE
DB
QUEUE
UI
API
EXTERNAL
SERVICES
API CONTRACTS
Spring MVC
Spring MVC
Spring Data
Spring
Messaging
RestTemplate
Feign
Spring Cloud
Contracts

21. You could work on business logic

22. Better focus
helps to achieve
better results

24. There are still some blockers
#1. Transactions
#2. Validation
#3. Thick client
#4. DB tuning
#5. Thinking model

25. Summary
• Change your point of view from layered approach
• Start using ports and adapters approach
• Make business logic use case driven
• Learn how to use existing Spring Boot modules
• Adopt Domain Driven Design ideas
• Be happy unicorn in the rainbow world ;)

27. @xpinjection
http://xpinjection.com
mikalai.alimenkou@xpinjection.com