Ambiguous @ExceptionHandler method mapped for MethodArgumentNotValidException and NoHandlerFoundException

Question

I have a requirement to use the NoHandlerFoundException exception handler within my global exception handler.

I was already using the MethodArgumentNotValidException handler by overriding it from the extended ResponseEntityExceptionHandler class.

Now, while running the application, I am getting this exception.

I was using the method Argument Not valid handler to handle the missing fields inside my request body.

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.HandlerExceptionResolver]: Factory method 'handlerExceptionResolver' threw exception with message: Ambiguous @ExceptionHandler method mapped for [class org.springframework.web.bind.MethodArgumentNotValidException]: {protected org.springframework.http.ResponseEntity com.kroger.iwt.coreservice.exception.handler.GlobalExceptionHandler.handleMethodArgumentNotValid(org.springframework.web.bind.MethodArgumentNotValidException,org.springframework.http.HttpHeaders,org.springframework.http.HttpStatusCode,org.springframework.web.context.request.WebRequest), public final org.springframework.http.ResponseEntity org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler.handleException(java.lang.Exception,org.springframework.web.context.request.WebRequest) throws java.lang.Exception}

@Slf4j
@ControllerAdvice
public class GlobalExceptionHandler extends ResponseEntityExceptionHandler {

    @ExceptionHandler({ NoHandlerFoundException.class })
    @ResponseBody
    @ResponseStatus(HttpStatus.NOT_FOUND)
    public ResponseEntity<ErrorListResponse> notFound(final NoHandlerFoundException exception) {
        log.error("{} {}", 404, exception.getMessage());
        ErrorListResponse errorListResponse = errorResponse("Request URI Not Found", exception);
        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(errorListResponse);
    }

    // @Override
    @ExceptionHandler(MethodArgumentNotValidException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    @ResponseBody
    protected ResponseEntity<Object> handleMethodArgumentNotValid(MethodArgumentNotValidException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request) {
        List<FieldError> errors = ex.getBindingResult().getFieldErrors();
        List<ErrorListResponse.ErrorDetails> errorDetails = new ArrayList<>();
        for (FieldError fieldError : errors) {
            ErrorListResponse.ErrorDetails error = new ErrorListResponse.ErrorDetails();
            error.setReason(fieldError.getDefaultMessage());
            error.setCode("BAD_REQUEST");
            error.setDatetime(new DateTimeResponse(Instant.now().toString(), "America/New_York"));
            errorDetails.add(error);
        }
        ErrorListResponse errorResponse = new ErrorListResponse();
        errorResponse.setErrors(errorDetails);
        log.error("{} {}", 400, "Multiple fields are invalid");
        return new ResponseEntity(errorResponse, HttpStatus.BAD_REQUEST);
    }
}

Answer 1

As you are extending the ResponseEntityExceptionHandler class and override its methods you should not use the @ExceptionHandler annotation.

Otherwise Spring's org.springframework.web.servlet.HandlerExceptionResolver will find more then one handler for the same exception class and report an error.

This is valid also for methods that just handle those exceptions. Even with a different signature and/or in a different class not extending ResponseEntityExceptionHandler. The exceptions are listed here:

@ExceptionHandler({
    HttpRequestMethodNotSupportedException.class,
    HttpMediaTypeNotSupportedException.class,
    HttpMediaTypeNotAcceptableException.class,
    MissingPathVariableException.class,
    MissingServletRequestParameterException.class,
    MissingServletRequestPartException.class,
    ServletRequestBindingException.class,
    MethodArgumentNotValidException.class,
    HandlerMethodValidationException.class,
    NoHandlerFoundException.class,
    NoResourceFoundException.class,
    AsyncRequestTimeoutException.class,
    ErrorResponseException.class,
    MaxUploadSizeExceededException.class,
    ConversionNotSupportedException.class,
    TypeMismatchException.class,
    HttpMessageNotReadableException.class,
    HttpMessageNotWritableException.class,
    MethodValidationException.class,
    BindException.class
})

Solution

Remove @ExceptionHandler annotations from the methods handling the same exceptions as in ResponseEntityExceptionHandler (listed above). For these exceptions you should always override the handler methods and not define your own ones.

Answer 2

This code worked for me. Just need to use this method definition removing headers, httpStatusCode and making argument as final worked for me. Also I need to remove the inheriting behaviour of ResponseEntityExceptionHandler other wise NohandlerException instantiation will not happen.

@ExceptionHandler({MethodArgumentNotValidException.class})
@ResponseStatus(HttpStatus.BAD_REQUEST)
protected ResponseEntity<Object> handleMethodArgumentNotValid(final MethodArgumentNotValidException ex) {
    List<FieldError> errors = ex.getBindingResult().getFieldErrors();
    List<ErrorListResponse.ErrorDetails> errorDetails = new ArrayList<>();
    for (FieldError fieldError : errors) {
        ErrorListResponse.ErrorDetails error = new ErrorListResponse.ErrorDetails();
        error.setReason(fieldError.getDefaultMessage());
        error.setCode("BAD_REQUEST");
        error.setDatetime(new DateTimeResponse(Instant.now().toString(), "America/New_York"));
        errorDetails.add(error);
    }
    ErrorListResponse errorResponse = new ErrorListResponse();
    errorResponse.setErrors(errorDetails);
    log.error("{} {}", 400, "Multiple fields are invalid");
    return new ResponseEntity(errorResponse, HttpStatus.BAD_REQUEST);
}


    @ExceptionHandler({ NoHandlerFoundException.class })
public ResponseEntity<ErrorListResponse> notFound(final NoHandlerFoundException exception) {
    log.error("{} {}", 404, exception.getMessage());
    ErrorListResponse errorListResponse = errorResponse("Request URI Not Found", exception);
    return ResponseEntity.status(HttpStatus.NOT_FOUND).body(errorListResponse);
}