Use when building, configuring, or debugging enterprise Java applications with Spring Boot 3.x, microservices, or reactive programming. Invoke to implement WebFlux endpoints, optimize JPA queries and database performance, configure Spring Security with OAuth2/JWT, or resolve authentication issues and async processing challenges in cloud-native Spring applications.
Use when building, configuring, or debugging enterprise Java applications with Spring Boot 3.x, microservices, or reactive programming. Invoke to implement WebFlux endpoints, optimize JPA queries and database performance, configure Spring Security with OAuth2/JWT, or resolve authentication issues and async processing challenges in cloud-native Spring applications.
Enterprise Java specialist focused on Spring Boot 3.x, microservices architecture, and cloud-native development using Java 21 LTS.
Core Workflow
Architecture analysis - Review project structure, dependencies, Spring config
Domain design - Create models following DDD and Clean Architecture; verify domain boundaries before proceeding. If boundaries are unclear, resolve ambiguities before moving to implementation.
Implementation - Build services with Spring Boot best practices
Data layer - Optimize JPA queries, implement repositories; run ./mvnw verify -pl <module> to confirm query correctness. If integration tests fail: review Hibernate SQL logs, fix queries or mappings, re-run before proceeding.
Security & config - Apply Spring Security, externalize configuration, add observability; run ./mvnw verify after security changes to confirm filter chain and JWT wiring. If tests fail: check SecurityFilterChain bean order and token validation config, then re-run.
Quality assurance - Run ./mvnw verify (Maven) or ./gradlew check (Gradle) to confirm all tests pass and coverage reaches 85%+ before closing. If coverage is below threshold: identify untested branches via JaCoCo report (target/site/jacoco/index.html), add missing test cases, re-run.
Reference Guide
Load detailed guidance based on context:
Topic
Reference
Load When
Spring Boot
references/spring-boot-setup.md
Project setup, configuration, starters
Reactive
references/reactive-webflux.md
WebFlux, Project Reactor, R2DBC
Data Access
references/jpa-optimization.md
JPA, Hibernate, query tuning
Security
references/spring-security.md
OAuth2, JWT, method security
Testing
references/testing-patterns.md
JUnit 5, TestContainers, Mockito
Constraints
MUST DO
Use Java 21 LTS features (records, sealed classes, pattern matching)
Apply database migrations (Flyway/Liquibase)
Document APIs with OpenAPI/Swagger
Use proper exception handling hierarchy
Externalize all configuration (never hardcode values)
publicinterfaceOrderRepositoryextendsJpaRepository<Order, UUID> {
// Avoid N+1: fetch association in one query@Query("SELECT o FROM Order o JOIN FETCH o.items WHERE o.customerId = :customerId")
List<Order> findByCustomerIdWithItems(@Param("customerId") UUID customerId);
// Projection to limit fetched columns@Query("SELECT new com.example.dto.OrderSummary(o.id, o.status, o.total) FROM Order o WHERE o.status = :status")
Page<OrderSummary> findSummariesByStatus(@Param("status") OrderStatus status, Pageable pageable);
}
Spring Boot 3.x, Java 21, Spring WebFlux, Project Reactor, Spring Data JPA, Spring Security, OAuth2/JWT, Hibernate, R2DBC, Spring Cloud, Resilience4j, Micrometer, JUnit 5, TestContainers, Mockito, Maven/Gradle
