Spring: Convert String from View to a Calendar Object

How can I convert a string from a form input (easyui-datetimebox, in case) to a Calendar property in an object in Controller, autobinded by Spring?

I've read http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/validation.html but I couldn't find anything nearly right-to-the-point there.

JSP:

<input id="DeadLineDate"
  class="easyui-datetimebox" 
  name="DeadLineDate"
  value="${SessionDeadLineDate}"
  data-options="formatter:myformatter,
                parser:myparser
/>

When submited, Spring validation throws an error:

Failed to convert property value of type java.lang.String to required type java.util.Calendar for property DeadLineDate; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [java.util.Calendar] for property DeadLineDate: no matching editors or conversion strategy found.

PS: Spring 3

Edit: adding controller's method to perform operation:

@Controller
@RequestMapping("/project/MaintainProjectFrm")
@SessionAttributes({"project","SessionDeadLineDate"})
public class MaintainProjectController {

    /* ... many methods... */

    @RequestMapping(params = "update", method = RequestMethod.POST, produces={"text/plain; charset=UTF-8"})
    public String update(@ModelAttribute("project") Project project, 
                            BindingResult result, 
                                    SessionStatus status, 
                                        ModelMap model,
                                            HttpServletRequest req,
                                                HttpServletResponse resp) throws IOException {

        projectValidator.validate(project, result);

        if (result.hasErrors()) {
             //has errors, in this case, that one shown in text above, which is rendered again in view (JSP)
            return "/project/MaintainProjectFrm";
        } else {

            try{
                mpService.updateProject(project);
            }
            catch(Exception e){
                resp.setStatus(500);
                resp.getWriter().write("Error updating project: " + e.getMessage());
                return "/project/MaintainProjectFrm";
            }

            status.setComplete();

        }
    }

    /* ... yet other methods ... */
}