Im struggling with showing an error that isn't related to a bind attribute:

Controller:
	@RequestMapping(value = "/module/appointment/appointmentList", method = RequestMethod.POST)
	public void onSubmit(HttpServletRequest request, @ModelAttribute("appointmentList") List<Appointment> appointmentList,
	        Errors errors, @RequestParam(value = "selectAppointment", required = false) Appointment selectedAppointment,
	        ModelMap model, @RequestParam(value = "fromDate", required = false) Date fromDate,
	        @RequestParam(value = "toDate", required = false) Date toDate) {
		if (fromDate != null && toDate != null && !fromDate.before(toDate)) {
			errors.reject("appointment.Appointment.error.InvalidDateInterval");
			model.put("errors", errors);
			return;
		}
....
	}


JSP:
<form:form method="post" modelAttribute="selectedAppointment" id="manageAppointmentsForm">
<form:errors cssClass="error" element="div"/>