@ControllerAdvice
public class CustomResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {

    @Override
    protected ResponseEntity<Object> handleMethodArgumentNotValid(MethodArgumentNotValidException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
        List<FieldError> fieldErrors = ex.getBindingResult().getFieldErrors();
        List<ObjectError> globalErrors = ex.getBindingResult().getGlobalErrors();
        List<String> errors = new ArrayList<>(fieldErrors.size() + globalErrors.size());
        String error;
        for (FieldError fieldError : fieldErrors) {
            error = fieldError.getField() + ", " + fieldError.getDefaultMessage();
            errors.add(error);
        }
        for (ObjectError objectError : globalErrors) {
            error = objectError.getObjectName() + ", " + objectError.getDefaultMessage();
            errors.add(error);
        }
        ErrorMessage errorMessage = new ErrorMessage(errors);
        return new ResponseEntity(errorMessage, headers, status);
    }

    @Override
    protected ResponseEntity<Object> handleHttpMediaTypeNotSupported(HttpMediaTypeNotSupportedException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
        String unsupported = "Unsupported content type: " + ex.getContentType();
        String supported = "Supported content types: " + MediaType.toString(ex.getSupportedMediaTypes());
        ErrorMessage errorMessage = new ErrorMessage(unsupported, supported);
        return new ResponseEntity(errorMessage, headers, status);
    }

    @Override
    protected ResponseEntity<Object> handleHttpMessageNotReadable(HttpMessageNotReadableException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
        Throwable mostSpecificCause = ex.getMostSpecificCause();
        ErrorMessage errorMessage;
        if (mostSpecificCause != null) {
            String exceptionName = mostSpecificCause.getClass().getName();
            String message = mostSpecificCause.getMessage();
            errorMessage = new ErrorMessage(exceptionName, message);
        } else {
            errorMessage = new ErrorMessage(ex.getMessage());
        }
        return new ResponseEntity(errorMessage, headers, status);
    }
}