Spring custom validator class with MultipartFile class support does not get called/fired - spring

Question

Sorry i couldn't find a better way to construct the question.
I am trying to validate on server side an array of multipartfile received with other information (e.g email, phone number etc) from an Ajax multipart/form-data post request.
I created 2 custom validator classes by implementing Spring Validator interface, UserFilesValidator to check that all received files are image files and are not above 2MB
and UserInfosValidator to check other user information e.g. phone number validate, email avalibility etc.
I registered the custom validator classes using #InitBinder.
Now when request is made, UserInfosValidator gets called and works fine but UserFilesValidator doesn't get called
Here is my code
Controller class
#Controller
public class UserController{
private final UserFilesValidator userFilesValidator;
private final UserInfosValidator userInfosValidator;
#Autowired
public UserController(UserFilesValidator userFilesValidator, UserInfosValidator userInfosValidator){
this.userFilesValidator = userFilesValidator;
this.userInfosValidator = userInfosValidator;
}
#InitBinder("userfiles")
public void formDataBinder1(WebDataBinder binder){
binder.addValidators(userFilesValidator);
}
#InitBinder("userinfos")
public void formDataBinder2(WebDataBinder binder){
binder.addValidators(userInfosValidator);
}
#RequestMapping(value = "/add", method = RequestMethod.POST, produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
#ResponseBody
public ResponseEntity<UserEntity> addUser(#RequestParam("userfiles") #Valid MultipartFile[] files,
#RequestPart("userinfos") #Valid UserEntity user){
//codes ...
}
}
Validator class
#Component
public class UserFilesValidator implements Validator {
#Override
public boolean supports(Class<?> clazz) {
return MultipartFile[].class.isAssignableFrom(clazz);
}
#Override
public void validate(Object target, Errors errors) {
MultipartFile[] files = (MultipartFile[]) target;
//validation codes ...
}
}
I excluded UserInfosValidator class since it works fine.
I also did not included global exception handler class (that's #ControllerAdvice annotated class)
since errors has to be registered in UserFilesValidator class which is not even getting called.
So please how can i get this to work? I know i can validate it in addUser method but I don't want to have validation codes in controller class
request handler method.