🍃☕ SPRING MODULITH 2.2 M1: modular monoliths move to BOOT 4.2
🍃☕ SPRING MODULITH 2.2 M1: modular monoliths move to BOOT 4.2
Keep the monolith. Make its boundaries executable.
🔸 TLDR
Spring Modulith helps turn a Spring Boot monolith into explicit, domain-driven modules whose boundaries can be verified, tested, observed and documented.
2.2 M1 moves to Spring Boot 4.2 M1 + Spring Framework 7.1 M1, while improving events, testing and auto-configuration.
🔸WHAT IS SPRING MODULITH?
A modular monolith keeps one deployable application while organizing the code into business-oriented modules.
Instead of hoping developers respect package boundaries, Spring Modulith can inspect and enforce them.
Think:
▪️ one application
▪️ multiple domain modules
▪️ explicit dependencies
▪️ architecture tests
▪️ module-focused integration tests
▪️ events between modules
You keep the operational simplicity of a monolith without accepting a giant ball of mud. 🧱
1️⃣ DECLARE MODULE DEPENDENCIES
@org.springframework.modulith.ApplicationModule(
allowedDependencies = "inventory"
)
package example.order;The order module explicitly declares what it may depend on. This turns architectural intent into a rule the codebase can verify instead of leaving it buried in a diagram or README.
#ModularArchitecture
2️⃣ VERIFY THE ARCHITECTURE
@Test void verifyModules() { ApplicationModules .of(Application.class) .verify(); }
verify() checks the module model for problems such as dependency cycles, access to another module's internals and violations of explicitly allowed dependencies.
Architecture becomes executable. ✅
#ArchitectureTesting
3️⃣ TEST ONE MODULE
@ApplicationModuleTest class OrderModuleTests { @Test void createsOrder() { // test the order module } }
@ApplicationModuleTest boots the application around the module being tested instead of treating the entire application as one inseparable unit.
Smaller boundary. More focused integration test. 🎯
#SpringTesting
https://javafullstack2027.mystrikingly.com
🔸 WHY THIS MATTERS
Microservices are not the only way to create boundaries.
Spring Modulith gives you many of the architectural benefits first:
▪️ domain-oriented decomposition
▪️ controlled dependencies
▪️ event-driven collaboration
▪️ architectural verification
▪️ module-level observability
▪️ generated architecture documentation
...without immediately paying the distributed-system tax. 💸
🔸 6️⃣ WHAT'S NEW IN SPRING MODULITH 2.2 M1?
The first milestone of 2.2 mainly modernizes the platform underneath Modulith.
🚀 Platform alignment
▪️ Spring Boot 4.2 M1
▪️ Spring Framework 7.1 M1
▪️ ArchUnit 1.5.0
▪️ Micrometer Tracing 1.7.1
📨 Events & Outbox
▪️ Namastack Outbox 1.8.1
▪️ improved Namastack version management
▪️ event externalization ClassCastException fix
⚙️ Auto-configuration
▪️ modernized registration for moments, events and observability modules
▪️ Jackson 2 configuration conflict fixed
🧪 Testing
▪️ fresh SQL Testcontainers are now ensured
▪️ JUnit parallel execution issue fixed
▪️ root-module Flyway migration test issue fixed
▪️ MongoDB publication tests correctly use Testcontainers
Spring Modulith 2.2 M1 is a milestone, so it is more interesting as a preview of the next generation than as the version you blindly drop into production.
🔸 DEMO REPOSITORY
I built a Spring Modulith 2.2 M1 demo with order and inventory modules, H2, module dependency rules, verifyModules() architecture checks and @ApplicationModuleTest with createsOrder().
A small repo to see the concepts running, not just diagrammed.
🔸 TAKEAWAYS
▪️ Modulith ≠ microservices inside one JVM.
▪️ Its real value is making module boundaries explicit and enforceable.
▪️ ApplicationModules.verify() turns architecture into a testable constraint.
▪️ @ApplicationModuleTest gives integration testing a domain-module boundary.
▪️ 2.2 M1 aligns that model with the upcoming Spring Boot 4.2 / Framework 7.1 generation.
A well-designed monolith is not the architecture you failed to split.
Sometimes, it is the architecture you deliberately chose. 🧩
#Java #Spring #SpringBoot #SpringModulith #ModularMonolith #SoftwareArchitecture #DDD #DomainDrivenDesign #Architecture #Microservices #Testing #JavaDeveloper
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