What is the difference between @ControllerAdvice and @RestControllerAdvice?

@RestControllerAdvice combines @ControllerAdvice with @ResponseBody, meaning all handler methods automatically serialize return values to the response body (typically JSON). Use @RestControllerAdvice for REST APIs and @ControllerAdvice when you need to return ModelAndView objects for server-rendered HTML error pages.

How does Spring determine which @ExceptionHandler method to invoke when multiple handlers exist?

Spring selects the most specific handler first. An exact class match (e.g., ResourceNotFoundException.class) wins over a parent class match (e.g., RuntimeException.class). If multiple @ControllerAdvice classes handle the same exception, use @Order annotations to control precedence — lower values execute first. Within a single advice class, the most specific exception type takes priority.

What is ProblemDetail in Spring 6 and how does it relate to RFC 7807?

ProblemDetail is a Spring 6+ class that implements the RFC 7807 'Problem Details for HTTP APIs' standard. It produces a standardized JSON structure with fields like type, title, status, detail, and instance. Enable it globally with spring.mvc.problemdetails.enabled=true to automatically convert standard Spring exceptions into RFC 7807 responses. You can extend it with custom properties using setProperty() for domain-specific error metadata.

Should I use ResponseStatusException or custom exception classes in Spring Boot?

Use custom exception classes for recurring, domain-specific errors (ResourceNotFoundException, InsufficientFundsException) because they provide type safety, consistent error codes, and are testable. Use ResponseStatusException for one-off or prototyping situations where creating a full class feels excessive. In mature codebases, custom exceptions with @ControllerAdvice produce cleaner, more maintainable code.

How do I include request context like a request ID in Spring Boot error logs?

Use MDC (Mapped Diagnostic Context) in a servlet filter: extract or generate a request ID, call MDC.put('requestId', id) before the filter chain executes, and MDC.clear() in a finally block. Configure your logging pattern (e.g., Logback) to include %X{requestId}. This ensures every log line — including those from @ExceptionHandler methods — carries the request ID for end-to-end tracing.

Spring Boot Exception Handling