Как работать с HashMap в JSP

При попытке собрать HashMap со значениями Long - ключ , Boolean - значение выскакивает ошибка "Invalid property '45' of bean class [java.util.HashMap]: Bean property '45' is not readable or has an invalid getter method: Does the return type of the getter match the parameter type of the setter?" (45 в данном случае - ключ по которому надо занести значение)

Мой контроллер:

@Controller
public class FlowController {
@Autowired
private TestInterfaceService testService;
@Autowired
private ResultCalcInterfaceService resCalc;
@Autowired
private UserService userService;
@Autowired
private SecurityService securityService;
@Autowired
private QuestionInterfaceService questionService;
@Autowired
private ResultInterfaceService resService;
@RequestMapping(value = "/testPassing/{id}", method = RequestMethod.GET)
public String testPassing(@PathVariable("id") long id, Model model) {
    Test test = this.testService.getFullTestById(id);
    model.addAttribute("ourTest", test);
    return "testPassing";
}
@RequestMapping(value = "/passing/{id}")
public String startPassing(@PathVariable("id") long id, @RequestParam(required = false) Integer qId, Model model) {
    Test test = this.testService.getFullTestById(id);
    Date date = resService.addResult(test, userService.findByUsername(securityService.getName()));
    model.addAttribute("passingTest", test);
    int pageSize = test.getQuestions().size();
    List<Question> questions = test.getQuestions();
    model.addAttribute("questionSize", test.getQuestions().size());
    SimpleDateFormat formatter = new SimpleDateFormat("MMM d, yyyy HH:mm:ss", Locale.ENGLISH);
    String dateString = formatter.format(date);
    model.addAttribute("ourDate", dateString);
    model.addAttribute("Long", new Long(0));
    if (qId == null || qId < 1 || qId > pageSize) {
        qId = 1;
        model.addAttribute("questionId", questions.get(qId).getId());
        model.addAttribute("question", questions.get(qId));
        HashMap<Long, Boolean> listAnswers = questionService.getAnswerList(questions.get(qId));
        model.addAttribute("listAnswers", listAnswers);
    } else if (qId <= pageSize) {
        model.addAttribute("questionId", qId);
        model.addAttribute("question", questions.get(qId - 1));
        HashMap<Long, Boolean> listAnswers = questionService.getAnswerList(questions.get(qId - 1));
        model.addAttribute("listAnswers", listAnswers);
    }
    return "testPassing";
}
@RequestMapping(value = "/setAnswer/{questionId}", method = RequestMethod.GET)
public String setAnswer(@ModelAttribute("listAnswers") HashMap<Long, Boolean> listAnswers,
        @PathVariable("questionId") long questionId, Model model) {
    Question question = questionService.getQuestionById(questionId);
    System.out.println(listAnswers);
    HashMap<Long, Boolean> listAnswers2 = listAnswers;
    resCalc.setAnswer(userService.findByUsername(securityService.getName()), question, listAnswers2);
    Test test = question.getqTest();
    return "redirect:/passing/" + test.getId();
}
}

Мой JSP :

        <form:form
        action="${pageContext.request.contextPath}/setAnswer/${questionId}"
        modelAttribute="listAnswers" method="GET">
        <table>
            <c:forEach items="${listAnswers}" var="answer" varStatus="status">
                <tr>
                    <td>${answer}</td>
                    <td><form:select path="${answer.key}" value="${answer.value}" /></td>
                </tr>
            </c:forEach>
        </table>
        <br />
        <input type="submit" value="Save" />
    </form:form>

П.с. если заменить form:select на input / select то в контроллер прилетает null а не лист выбора пользователя