<form name='form' th:object="${role}" method='GET'>
        <table>
            <tr>
                <td>Rol sec</td>
                <td>
                    <select class="form-control"
                            th:field="${roleList}" >


                        <option value="0">
                            Rol seciniz
                        </option>
                        <option th:each="role : ${roleList}"
                                th:value="${role.id}"
                                th:text="${role.name}">

                        </option>
                    </select>

                </td>
            </tr>

            <tr>
                <td><input name="submit" type="submit" value="Sec" /></td>
            </tr>
        </table>
    </form>

@GetMapping(value = {"/assign-roles"})
...
    modelView.addObject("roleList", roleService.findAll());

    return modelView;
}

th:action="${'/menu/id'}"

@GetMapping("/{id}")
    public ModelAndView getMenusForRole(@PathVariable String id) {


//same modelview

        modelView.addObject("menuList", menuService.findAllMenusForRole(id));

        return modelView;
    }