Layered monolith §

Contact me for information about consulting and training at your company.

Until June 25th, enroll for $95 in my virtual bootcamp, distributed data patterns in a microservice architecture


Context §

Teams own one or more subdomains/bounded contexts.

subdomains/bounded contexts consists of different types of logic:

  • web - e.g. REST controllers
  • domain - business logic
  • persistence - data access logic.

Forces §

  • Simple components
  • Team autonomy
  • Fast deployment pipeline
  • Support multiple technology stacks
  • Segregate by characteristics
  • Minimize design-time coupling
  • Maximize cohesion

Problem §

How to structure the monolith/component? How to organize the subdomains/bounded contexts to form a monolith/component?

Domain view: comprised of packages, package hierarchy (and classes)

Component view: comprised of Maven/Gradle modules

Solution §

Structure the monolith/component as a collection of technically-oriented layers, e.g. web, domain, and persistence.

Domain - Packages: com.<company>.<application>.<layer>.<domain>

Component - Maven/Gradle module: web, domain, persistence

  • I suppose a layer could consist of multiple Maven/Gradle modules.

Implementation of a subdomain/bounded context is spread across the layers.

JPA - what’s the actual layers:

interface CustomerRepository extends JpaRepository<Customer, Long> {}

This can’t be in a persistence layer, because that creates a circular dependency.

Could have DAOs and DTOs in the persistence layer

Domain layer API:

  • Old school - DTOs
  • New school - Open Session in View

Variation §

Technically-oriented hexagonal architecture.

Domain - Packages: com.<company>.<application>.<adapter-X|domain>

Component - Maven/Gradle module: adapter-X, domain

Resulting context §

  • Simple, familiar
  • JPA entities can reference each other

Benefits §

Drawbacks §

  • Simple components
  • Team autonomy
  • Fast deployment pipeline
  • Support multiple technology stacks
  • Segregate by characteristics
  • Minimize design-time coupling
  • Maximize cohesion

Issues §

Motivating patterns §

Alternatives §

‘Successor patterns’ §



Copyright © 2025 Chris Richardson • All rights reserved • Supported by Kong.

About Microservices.io

Microservices.io is brought to you by Chris Richardson. Experienced software architect, author of POJOs in Action, the creator of the original CloudFoundry.com, and the author of Microservices patterns.

ASK CHRIS

?

Got a question about microservices?

Fill in this form. If I can, I'll write a blog post that answers your question.

ASSESS your architecture

Assess your application's microservice architecture and identify what needs to be improved. Engage Chris to conduct an architect review.

LEARN about microservices

Chris offers numerous other resources for learning the microservice architecture.

Get the book: Microservices Patterns

Read Chris Richardson's book:

Example microservices applications

Want to see an example? Check out Chris Richardson's example applications. See code

Virtual bootcamp: Distributed data patterns in a microservice architecture

My virtual bootcamp, distributed data patterns in a microservice architecture, is now open for enrollment!

It covers the key distributed data management patterns including Saga, API Composition, and CQRS.

It consists of video lectures, code labs, and a weekly ask-me-anything video conference repeated in multiple timezones.

The regular price is $395/person but use coupon OGDQZDTI to sign up for $95 (valid until June 25th, 2025). There are deeper discounts for buying multiple seats.

Learn more

Learn how to create a service template and microservice chassis

Take a look at my Manning LiveProject that teaches you how to develop a service template and microservice chassis.

Signup for the newsletter


BUILD microservices

Ready to start using the microservice architecture?

Consulting services

Engage Chris to create a microservices adoption roadmap and help you define your microservice architecture,


The Eventuate platform

Use the Eventuate.io platform to tackle distributed data management challenges in your microservices architecture.

Eventuate is Chris's latest startup. It makes it easy to use the Saga pattern to manage transactions and the CQRS pattern to implement queries.


Join the microservices google group