version: "1.0.0" name: java-springboot-development description: CIEL's framework for Java 17+ and Spring Boot 3+ development, security, and TDD. license: MIT metadata: ciel-version: 1.0.0 ciel-extension: ciel.yaml

CIEL ADAPTATION: Java & Spring Boot (The Enterprise Layer)

This skill formalizes the development of production-grade Java services using Spring Boot. It mandates immutability, fail-fast error handling, and security-first configuration.

Java Standards (17+)

1. Immutability: Favor record and final fields. No setters.
2. Null Safety: Accept @Nullable only when unavoidable. Use Optional for return types.
3. Fail Fast: Use domain-specific unchecked exceptions (e.g., EntityNotFoundException).
4. Streams: Keep pipelines short and readable. Favor List.of() and .toList().

Spring Boot Architecture

• Layered Discipline: Controller (thin) -> Service (pure logic) -> Repository (abstract access).
• Injection: Use constructor injection; prohibit @Autowired on fields.
• Transactions: Use @Transactional(readOnly = true) for all GETs.
• Validation: Enforce @Valid on all RequestBody DTOs via Bean Validation (Zod-like patterns).

Security Review

• Auth: Default to stateless JWT. Use OncePerRequestFilter for validation.
• CSRF: Disable for pure APIs; Enable for session-based browser apps.
• SQLi: Prohibit string concatenation in @Query. Use :param bindings only.
• PII: Never log full payloads or sensitive fields. Redact centrally.

TDD Workflow

• Unit: JUnit 5 + AssertJ + Mockito. 100% logic coverage.
• Web: MockMvc for controller boundary testing.
• Persistence: DataJpaTest with Testcontainers (no H2 in CI).

Anti-Patterns

• Lombok Over-use: Using @Data on immutable domain entities (use @Value or record).
• Magic Numbers: Hardcoding timeouts or page sizes.
• Silent Catch: Catching Exception without rethrowing or structured logging.