Spring Validation, form doesn't show error message

Question

Why form in my "addcar" view doesn't show message?

My Controller method

@RequestMapping(value = "/add-car", method = RequestMethod.POST)
public String addCar(@ModelAttribute("carDto") @Valid CarDto carDto, 
BindingResult bindingResult, ModelMap modelMap) {

    if (bindingResult.hasErrors()) {
        if (carDto.isDealerCar() == false) {
            String status = "userCession";
            boolean dealerCar = false;
            boolean accepted = false;
            int numberOfTestDrives = 0;
            modelMap.addAttribute("carDto", new CarDto());
            modelMap.addAttribute("status", status);
            modelMap.addAttribute("dealerCar", dealerCar);
            modelMap.addAttribute("accepted", accepted);
            modelMap.addAttribute("numberOfTestDrives", numberOfTestDrives);
            return "car/addcar";
        }

My Form sample (addcar view)

        <div class="form-group">
            <h3>
                <span class="label label-default">Numer VIN</span>
            </h3>
            <input type="text" class="form-control" th:field="*{vin}" />
            <div class="alert alert-warning" 
                 th:if="${#fields.hasErrors('vin')}">
                <span th:errors="*{vin}">Error</span>
            </div>
        </div>

It worked when i just return to my addcar view but it pass without my set values, and i cannot submit form. When it is like above, new form pass but without error message.

Answer 1

you can try:

public String addCar(@requestParam (Map) ) {