Backend

Unit testing Jakarta Bean Validation (@Valid, @NotNull, @Min, @Max, etc.) with custom validators and constraint violations. Test validation logic without Spring context. Use when ensuring data integrity and validation rules are correct.

Implement Event-Driven Architecture (EDA) in Spring Boot using ApplicationEvent, @EventListener, and Kafka. Use for building loosely-coupled microservices with domain events, transactional event listeners, and distributed messaging patterns.

Provide repeatable CRUD workflows for Spring Boot 3 services with Spring Data JPA and feature-focused architecture; apply when modeling aggregates, repositories, controllers, and DTOs for REST APIs.

Amazon DynamoDB patterns using AWS SDK for Java 2.x. Use when creating, querying, scanning, or performing CRUD operations on DynamoDB tables, working with indexes, batch operations, transactions, or integrating with Spring Boot applications.

Amazon Bedrock patterns using AWS SDK for Java 2.x. Use when working with foundation models (listing, invoking), text generation, image generation, embeddings, streaming responses, or integrating generative AI with Spring Boot applications.

Integration patterns for LangChain4j with Spring Boot. Auto-configuration, dependency injection, and Spring ecosystem integration. Use when embedding LangChain4j into Spring Boot applications.

Instruction set for enabling and operating the Spring Cache abstraction in Spring Boot when implementing application-level caching for performance-sensitive workloads.

Dependency injection workflow for Spring Boot projects covering constructor-first patterns, optional collaborator handling, bean selection, and validation practices.

Testing Spring application events (ApplicationEvent) with @EventListener and ApplicationEventPublisher. Test event publishing, listening, and async event handling in Spring Boot applications. Use when validating event-driven workflows in your Spring Boot services.

AWS Lambda patterns using AWS SDK for Java 2.x. Use when invoking Lambda functions, creating/updating functions, managing function configurations, working with Lambda layers, or integrating Lambda with Spring Boot applications.

Configure Spring Boot Actuator for production-grade monitoring, health probes, secured management endpoints, and Micrometer metrics across JVM services.

Unit tests for Spring Security with @PreAuthorize, @Secured, @RolesAllowed. Test role-based access control and authorization policies. Use when validating security configurations and access control logic.

Expert in Spring Data Neo4j integration patterns for graph database development. Use when working with Neo4j graph databases, node entities, relationships, Cypher queries, reactive Neo4j operations, or Spring Data Neo4j repositories. Essential for graph data modeling, relationship mapping, custom queries, and Neo4j testing strategies.

Configure AWS RDS (Aurora, MySQL, PostgreSQL) with Spring Boot applications. Use when setting up datasources, connection pooling, security, and production-ready database configuration.

This skill should be used when implementing fault tolerance and resilience patterns in Spring Boot applications using the Resilience4j library. Apply this skill to add circuit breaker, retry, rate limiter, bulkhead, time limiter, and fallback mechanisms to prevent cascading failures, handle transient errors, and manage external service dependencies gracefully in microservices architectures.

Implement REST API design standards and best practices for Spring Boot projects. Use when creating or reviewing REST endpoints, DTOs, error handling, pagination, security headers, HATEOAS and architecture patterns.

Express.js framework patterns including routing, middleware, request/response handling, and Express-specific APIs. Use when working with Express routes, middleware, or Express applications.

Comprehensive NestJS framework guide with Drizzle ORM integration. Use when building NestJS applications, setting up APIs, implementing authentication, working with databases, or integrating Drizzle ORM. Covers controllers, providers, modules, middleware, guards, interceptors, testing, microservices, GraphQL, and database patterns.

AWS Secrets Manager patterns using AWS SDK for Java 2.x. Use when storing/retrieving secrets (passwords, API keys, tokens), rotating secrets automatically, managing database credentials, or integrating secret management into Spring Boot applications.

Unit tests for caching behavior using Spring Cache annotations (@Cacheable, @CachePut, @CacheEvict). Use when validating cache configuration and cache hit/miss scenarios.