What is Spring Boot's exception handling with @RestControllerAdvice?

// Centralised exception handler:
@RestControllerAdvice
public class GlobalExceptionHandler {

    private static final Logger log = LoggerFactory.getLogger(GlobalExceptionHandler.class);

    // Handle custom domain exception:
    @ExceptionHandler(OrderNotFoundException.class)
    @ResponseStatus(HttpStatus.NOT_FOUND)
    public ErrorResponse handleNotFound(OrderNotFoundException ex) {
        return new ErrorResponse(
            "ORDER_NOT_FOUND",
            ex.getMessage(),
            Instant.now()
        );
    }

    // Handle Bean Validation failures:
    @ExceptionHandler(MethodArgumentNotValidException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public ValidationErrorResponse handleValidation(MethodArgumentNotValidException ex) {
        Map<String, String> fieldErrors = ex.getBindingResult()
            .getFieldErrors()
            .stream()
            .collect(Collectors.toMap(
                FieldError::getField,
                FieldError::getDefaultMessage,
                (a, b) -> a  // keep first on duplicate key
            ));
        return new ValidationErrorResponse("VALIDATION_FAILED", fieldErrors);
    }

    // Handle illegal argument:
    @ExceptionHandler(IllegalArgumentException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public ErrorResponse handleIllegalArg(IllegalArgumentException ex) {
        return new ErrorResponse("INVALID_REQUEST", ex.getMessage(), Instant.now());
    }

    // Catch-all for unexpected exceptions:
    @ExceptionHandler(Exception.class)
    @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
    public ErrorResponse handleGeneral(Exception ex, HttpServletRequest request) {
        log.error("Unhandled exception for {}: {}", request.getRequestURI(), ex.getMessage(), ex);
        return new ErrorResponse("INTERNAL_ERROR", "An unexpected error occurred", Instant.now());
    }
}

public record ErrorResponse(String code, String message, Instant timestamp) {}