jsp java.lang.NumberFormatException: null

При добавление данных в бд ловлю ошибку java.lang.NumberFormatException: null

Находится в этой строке кода

int price = Integer.parseInt(request.getParameter("price")); \\ссылается на эту ошибку
    int number = Integer.parseInt(request.getParameter("number"));
    int manufacturer_details = Integer.parseInt(request.getParameter("manufacturer_details"));
    Watch newWatch = new Watch(brand, type, price, number, manufacturer_details); \\когда начинаю отлаживать вылетает на это месте.

Что может быть не правильным, помогите разобраться или привести пример правильного решения.

Полный код WatchServlet

@WebServlet("/")
public class WatchServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    private WatchDAO watchDAO;
@Override
public void init() {
    watchDAO = new WatchDAO();
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
    doGet(request, response);
}

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
    String action = request.getServletPath();

    try {
        switch (action) {
            case "/new":
                showNewForm(request, response);
                break;
            case "/insert":
                insertWatch(request, response);
                break;
            case "/delete":
                deleteWatch(request, response);
                break;
            case "/edit":
                showEditForm(request, response);
                break;
            case "/update":
                updateWatch(request, response);
                break;
            default:
                listWatch(request, response);
                break;
        }
    } catch (SQLException ex) {
        throw new ServletException(ex);
    }
}

private void listWatch(HttpServletRequest request, HttpServletResponse response)
throws SQLException, IOException, ServletException {
    List < Watch > listWatch = watchDAO.selectAllWatchs();
    request.setAttribute("listWatch", listWatch);
    RequestDispatcher dispatcher = request.getRequestDispatcher("watch-list.jsp");
    dispatcher.forward(request, response);
}

private void showNewForm(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
    RequestDispatcher dispatcher = request.getRequestDispatcher("watch-form.jsp");
    dispatcher.forward(request, response);
}

private void showEditForm(HttpServletRequest request, HttpServletResponse response)
throws SQLException, ServletException, IOException {
    int id = Integer.parseInt(request.getParameter("Id"));
    Watch existingWatch = watchDAO.selectWatch(id);
    RequestDispatcher dispatcher = request.getRequestDispatcher("watch-form.jsp");
    request.setAttribute("Watch", existingWatch);
    dispatcher.forward(request, response);

}

private void insertWatch(HttpServletRequest request, HttpServletResponse response)
throws SQLException, IOException {
    String brand = request.getParameter("brand");
    String type = request.getParameter("type");
    int price = Integer.parseInt(request.getParameter("price")); 
    int number = Integer.parseInt(request.getParameter("number"));
    int manufacturer_details = Integer.parseInt(request.getParameter("manufacturer_details"));
    Watch newWatch = new Watch(brand, type, price, number, manufacturer_details);
    watchDAO.insertWatch(newWatch);
    response.sendRedirect("list");
}

private void updateWatch(HttpServletRequest request, HttpServletResponse response)
throws SQLException, IOException {
    int id = Integer.parseInt(request.getParameter("id"));
    String brand = request.getParameter("brand");
    String type = request.getParameter("Type");
    int price = Integer.parseInt(request.getParameter("Price")); 
    int number = Integer.parseInt(request.getParameter("Number"));
    int manufacturer_details = Integer.parseInt(request.getParameter("Manufacturer Details"));
    Watch book = new Watch(id, brand, type, price, number, manufacturer_details);
    watchDAO.updateWatch(book);
    response.sendRedirect("list");
}

    private void deleteWatch(HttpServletRequest request, HttpServletResponse response)
    throws SQLException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        watchDAO.deleteWatch(id);
        response.sendRedirect("list");

    }
}

jsp

    <html>

    <head>
        <title>Watch Management Application</title>
        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
    </head>

    <body>

        <header>
            <nav class="navbar navbar-expand-md navbar-dark" style="background-color: tomato">
                <ul class="navbar-nav">
                    <li><a href="<%=request.getContextPath()%>/list" class="nav-link">Watch</a></li>
                </ul>
            </nav>
        </header>
        <br>
        <div class="container col-md-5">
            <div class="card">
                <div class="card-body">
                    <c:if test="${watch != null}">
                        <form action="update" method="post">
                    </c:if>
                    <c:if test="${watch == null}">
                        <form action="insert" method="post">
                    </c:if>

                    <caption>
                        <h2>
                            <c:if test="${watch != null}">
                                Edit Watch
                            </c:if>
                            <c:if test="${watch == null}">
                                Add New Watch
                            </c:if>
                        </h2>
                    </caption>

                    <c:if test="${watch != null}">
                        <input type="hidden" name="id" value="<c:out value='$' />" />
                    </c:if>

                    <fieldset class="form-group">
                        <label>Watch Brand</label> <input type="text" value="<c:out value='${watch.brand}' />" class="form-control" name="brand" required="required">
                    </fieldset>
                    <fieldset class="form-group">
                        <label>Type Mechanic\Quartz</label><input type="text" value="<c:out value='${watch.type}' />" class="form-control" name="type">
                    </fieldset>
                    <fieldset class="form-group">
                        <label>Price</label> <input type="number" value="<c:out value='${watch.price}' />" class="form-control" name="price">
                    </fieldset>
                    <fieldset class="form-group">
                        <label>Number</label> <input type="number" value="<c:out value='${watch.number}' />" class="form-control" name="number">
                    </fieldset>
                    <fieldset class="form-group">
                        <label>Manufacturer details</label> <input type="number" value="<c:out value='${watch.manufacturer_details}' />" class="form-control" name="Manufacturer_details">
                    </fieldset>

                    <button type="submit" class="btn btn-success">Save</button>
                    </form>
                </div>
            </div>
        </div>
    </body>

    </html>