Spring: @ControllerAdvice turns exceptions into consistent responses

One place decides the shape of every error, instead of try/catch scattered through controllers.

Code

@RestControllerAdvice
class ApiExceptionHandler {

    @ExceptionHandler(NoSuchElementException.class)
    ResponseEntity<ApiError> notFound(NoSuchElementException e) {
        return ResponseEntity.status(404).body(new ApiError("NOT_FOUND", e.getMessage()));
    }

    @ExceptionHandler(MethodArgumentNotValidException.class)
    ResponseEntity<ApiError> invalid(MethodArgumentNotValidException e) {
        return ResponseEntity.badRequest().body(new ApiError("INVALID", e.getMessage()));
    }
}

Output

Every endpoint now returns the same JSON error shape,
and controllers contain no error-handling code at all.

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Published 2026-08-11