@@ -0,0 +1,1188 @@
+// Copyright 2020 Google LLC%0A//%0A// Licensed under the Apache License, Version 2.0 (the %22License%22);%0A// you may not use this file except in compliance with the License.%0A// You may obtain a copy of the License at%0A//%0A//     https://www.apache.org/licenses/LICENSE-2.0%0A//%0A// Unless required by applicable law or agreed to in writing, software%0A// distributed under the License is distributed on an %22AS IS%22 BASIS,%0A// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.%0A// See the License for the specific language governing permissions and%0A// limitations under the License.%0Apackage servlets;%0A%0Aimport java.io.IOException;%0Aimport javax.servlet.annotation.WebServlet;%0Aimport javax.servlet.http.*;%0Aimport com.google.appengine.api.users.UserService;%0Aimport com.google.appengine.api.users.UserServiceFactory;%0Aimport util.UserAuthUtil;%0A%0A@WebServlet(%22/Invalidate%22)%0Apublic class InvalidateSessionServlet extends HttpServlet %7B%0A%0A  // Invalidate the HttpSession that holds the access token.%0A  @Override%0A  public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException %7B%0A    HttpSession session = request.getSession(true);%0A    session.invalidate();%0A  %7D%0A%7D%0A

create a servlet to invalidate a HttpSession