What is @ControllerAdvice / @RestControllerAdvice, and what is it used for? | Interview Question | TechyTalkWithDev

Spring Boot Interview Questions

254 Questions

What is @ControllerAdvice / @RestControllerAdvice, and what is it used for?

What is @ExceptionHandler and how does exception resolution work when it's used?

What is the default error response behavior in Spring Boot when no custom exception handling is set up?

How do you use @ResponseStatus, and how does it differ from ResponseEntity for error responses?

How does Bean Validation (@Valid / @Validated) work on a REST controller's request body?

How do you extract structured, field-level validation errors from a MethodArgumentNotValidException?

How do you write a custom Bean Validation constraint annotation?

What is the difference between checked and unchecked exceptions in the context of a Spring Boot service layer, and which does Spring prefer?

What is ResponseStatusException, and when would you use it instead of a custom exception class with @ResponseStatus?

Interview questions

Question 89 of 254

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What is @ControllerAdvice / @RestControllerAdvice, and what is it used for?

Exception Handling & Validation

@ControllerAdvice (and its REST-focused variant @RestControllerAdvice, which adds @ResponseBody) marks a class as a global, cross-cutting handler applied across all (or a filtered subset of) @Controller classes — most commonly used to centralize exception handling via @ExceptionHandler methods, so individual controllers don't each need their own duplicated try/catch or error-mapping logic.

Intermediate5 min

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#@ControllerAdvice#@RestControllerAdvice

Specificity Wins When Multiple @ExceptionHandler Methods Could Match

If a global @RestControllerAdvice has a handler for a broad exception type (e.g., Exception.class) and another for a more specific subtype (e.g., ResourceNotFoundException), Spring selects the most specific matching handler for the thrown exception's actual type — same principle as catch-block ordering, letting you define one broad fallback handler plus targeted overrides for specific cases.

One @RestControllerAdvice class centralizes exception → HTTP response mapping for every controller in the app

Centralized Exception Handling

java

@RestControllerAdvice
class GlobalExceptionHandler {
    @ExceptionHandler(ResourceNotFoundException.class)
    ResponseEntity<ErrorResponse> handleNotFound(ResourceNotFoundException ex) {
        return ResponseEntity.status(404).body(new ErrorResponse(ex.getMessage()));
    }
}