java-architect_skill

Overview

This skill provides senior-level guidance and code patterns for building enterprise Java applications using Spring Boot 3.x, Java 21, and reactive or microservice architectures. It focuses on production-ready design: Clean Architecture, SOLID principles, robust testing, and cloud-native practices. Use it to harden architecture, optimize data access, secure services, and accelerate delivery of scalable systems.

How this skill works

I inspect project structure, dependencies, Spring configuration, and runtime patterns to identify architectural risks and improvement opportunities. I produce concrete artifacts: domain models, service layers, repository interfaces, controllers, and test suites following Java 21 and Spring Boot 3.x conventions. For reactive apps I validate non-blocking flows and backpressure; for JPA I profile queries and propose optimizations. I also recommend CI/CD, migration, monitoring, and security configurations to make systems production-ready.

When to use it

• Designing or refactoring Spring Boot 3.x microservices
• Building reactive WebFlux applications with Project Reactor
• Optimizing JPA/Hibernate performance and queries
• Implementing OAuth2/JWT-based Spring Security
• Creating cloud-native services with resilience and observability
• Writing comprehensive tests with JUnit 5 and TestContainers

Best practices

• Follow Clean Architecture boundaries: controllers -> services -> repositories -> domain
• Prefer Java 21 features (records, sealed types, pattern matching) for expressive models
• Avoid blocking calls in reactive stacks; use R2DBC for DB access in WebFlux
• Enforce input validation and explicit transaction boundaries
• Automate DB migrations (Flyway or Liquibase) and document APIs with OpenAPI
• Use TestContainers, JUnit 5, and Mockito to achieve high test coverage and deterministic integration tests

Example use cases

• Refactor a monolith into bounded-context microservices with API contracts and messaging patterns
• Implement a WebFlux-based API gateway with non-blocking request aggregation and resilience4j retries
• Tune Hibernate mappings and queries to eliminate N+1 issues and reduce latency
• Add OAuth2 resource server + JWT validation and method-level authorization
• Create CI pipeline that runs TestContainers integration tests and publishes OpenAPI docs