--- name: spring-boot-engineer-05ae6815d867 description: Generates Spring Boot 3.x configurations, creates REST controllers, implements Spring Security 6 authentication flows, sets up Spring Data JPA repositories, and configures reactive WebFlux endpoints. Use when building Spring Boot 3.x applications, microservices, or reactive Java applications; invoke for Spring Data JPA, Spring Security 6, WebFlux, Spring Cloud integration, Java REST API design, or Microservices Java architecture. license: MIT metadata: author: https://github.com/Jeffallan company: https://synergetic.solutions version: "1.1.0" domain: backend triggers: Spring Boot, Spring Framework, Spring Cloud, Spring Security, Spring Data JPA, Spring WebFlux, Microservices Java, Java REST API, Reactive Java role: specialist scope: implementation output-format: code related-skills: java-architect, database-optimizer, microservices-architect, devops-engineer --- # Spring Boot Engineer ## Core Workflow 1. **Analyze requirements** — Identify service boundaries, APIs, data models, security needs 2. **Design architecture** — Plan microservices, data access, cloud integration, security; confirm design before coding 3. **Implement** — Create services with constructor injection and layered architecture (see Quick Start below) 4. **Secure** — Add Spring Security, OAuth2, method security, CORS configuration; verify security rules compile and pass tests. If compilation or tests fail: review error output, fix the failing rule or configuration, and re-run before proceeding 5. **Test** — Write unit, integration, and slice tests; run `./mvnw test` (or `./gradlew test`) and confirm all pass before proceeding. If tests fail: review the stack trace, isolate the failing assertion or component, fix the issue, and re-run the full suite 6. **Deploy** — Configure health checks and observability via Actuator; validate `/actuator/health` returns `UP`. If health is `DOWN`: check the `components` detail in the response, resolve the failing component (e.g., datasource, broker), and re-validate ## Reference Guide Load detailed guidance based on context: | Topic | Reference | Load When | |-------|-----------|-----------| | Web Layer | `references/web.md` | Controllers, REST APIs, validation, exception handling | | Data Access | `references/data.md` | Spring Data JPA, repositories, transactions, projections | | Security | `references/security.md` | Spring Security 6, OAuth2, JWT, method security | | Cloud Native | `references/cloud.md` | Spring Cloud, Config, Discovery, Gateway, resilience | | Testing | `references/testing.md` | @SpringBootTest, MockMvc, Testcontainers, test slices | ## Quick Start — Minimal Working Structure A standard Spring Boot feature consists of these layers. Use these as copy-paste starting points. ### Entity ```java @Entity @Table(name = "products") public class Product { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @NotBlank private String name; @DecimalMin("0.0") private BigDecimal price; // getters / setters or use @Data (Lombok) } ``` ### Repository ```java public interface ProductRepository extends JpaRepository { List findByNameContainingIgnoreCase(String name); } ``` ### Service (constructor injection) ```java @Service public class ProductService { private final ProductRepository repo; public ProductService(ProductRepository repo) { // constructor injection — no @Autowired this.repo = repo; } @Transactional(readOnly = true) public List search(String name) { return repo.findByNameContainingIgnoreCase(name); } @Transactional public Product create(ProductRequest request) { var product = new Product(); product.setName(request.name()); product.setPrice(request.price()); return repo.save(product); } } ``` ### REST Controller ```java @RestController @RequestMapping("/api/v1/products") @Validated public class ProductController { private final ProductService service; public ProductController(ProductService service) { this.service = service; } @GetMapping public List search(@RequestParam(defaultValue = "") String name) { return service.search(name); } @PostMapping @ResponseStatus(HttpStatus.CREATED) public Product create(@Valid @RequestBody ProductRequest request) { return service.create(request); } } ``` ### DTO (record) ```java public record ProductRequest( @NotBlank String name, @DecimalMin("0.0") BigDecimal price ) {} ``` ### Global Exception Handler ```java @RestControllerAdvice public class GlobalExceptionHandler { @ExceptionHandler(MethodArgumentNotValidException.class) @ResponseStatus(HttpStatus.BAD_REQUEST) public Map handleValidation(MethodArgumentNotValidException ex) { return ex.getBindingResult().getFieldErrors().stream() .collect(Collectors.toMap(FieldError::getField, FieldError::getDefaultMessage)); } @ExceptionHandler(EntityNotFoundException.class) @ResponseStatus(HttpStatus.NOT_FOUND) public Map handleNotFound(EntityNotFoundException ex) { return Map.of("error", ex.getMessage()); } } ``` ### Test Slice ```java @WebMvcTest(ProductController.class) class ProductControllerTest { @Autowired MockMvc mockMvc; @MockBean ProductService service; @Test void createProduct_validRequest_returns201() throws Exception { var product = new Product(); product.setName("Widget"); product.setPrice(BigDecimal.TEN); when(service.create(any())).thenReturn(product); mockMvc.perform(post("/api/v1/products") .contentType(MediaType.APPLICATION_JSON) .content("""{"name":"Widget","price":10.0}""")) .andExpect(status().isCreated()) .andExpect(jsonPath("$.name").value("Widget")); } } ``` ## Constraints ### MUST DO | Rule | Correct Pattern | |------|----------------| | Constructor injection | `public MyService(Dep dep) { this.dep = dep; }` | | Validate API input | `@Valid @RequestBody MyRequest req` on every mutating endpoint | | Type-safe config | `@ConfigurationProperties(prefix = "app")` bound to a record/class | | Appropriate stereotype | `@Service` for business logic, `@Repository` for data, `@RestController` for HTTP | | Transaction scope | `@Transactional` on multi-step writes; `@Transactional(readOnly = true)` on reads | | Hide internals | Catch domain exceptions in `@RestControllerAdvice`; return problem details, not stack traces | | Externalize secrets | Use environment variables or Spring Cloud Config — never `application.properties` | ### MUST NOT DO - Use field injection (`@Autowired` on fields) - Skip input validation on API endpoints - Use `@Component` when `@Service`/`@Repository`/`@Controller` applies - Mix blocking and reactive code (e.g., calling `.block()` inside a WebFlux chain) - Store secrets or credentials in `application.properties`/`application.yml` - Hardcode URLs, credentials, or environment-specific values - Use deprecated Spring Boot 2.x patterns (e.g., `WebSecurityConfigurerAdapter`) Maintained by [@jeffallan](https://github.com/jeffallan), Principal Consultant at [Synergetic Solutions](https://synergetic.solutions) [Documentation](https://jeffallan.github.io/claude-skills/skills/backend/spring-boot-engineer/) --- Source attribution: Jeffallan Original project: https://github.com/Jeffallan/claude-skills License: MIT License information: https://opensource.org/license/mit Original upstream instructions; downloaded from Mega AI Hub. ## Upstream license notice MIT License Copyright (c) 2026 Gabriel Moreira Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. # Mega AI Hub resource metadata Creator / publisher: Jeffallan Original project: https://github.com/Jeffallan/claude-skills Attribution basis: Upstream repository explicitly recorded in package mirror path Fields of work: Development & Engineering, Product Management Roles: Backend Developer, DevOps / SRE, Growth Product Manager, Product Manager, Technical Product Manager Specialties: Backend Tools: Java, Spring Boot Country applicability: Country not specified Classification basis: Source catalog labels Instruction SHA-256: dc5c62f65d1cf46ad042db14492446445f7a0586a3f22b08c78e42c38750824f