@@ -0,0 +1,638 @@
+package com.google.sps.utilities;%0Aimport com.google.gson.Gson;%0Aimport com.google.sps.utilities.CommonUtils;%0Aimport java.util.ArrayList;%0Aimport java.util.List;%0Aimport javax.servlet.http.HttpServlet;%0Aimport javax.servlet.http.HttpServletRequest;%0Aimport javax.servlet.http.HttpServletResponse;%0A%0Apublic class CommonUtils %7B%0A  public static String convertToJson(Object object) %7B%0A    return new Gson().toJson(object);%0A  %7D%0A%0A  public static String getParameter(HttpServletRequest request, String name, String defaultValue) %7B%0A    String value = request.getParameter(name);%0A    return (value == null %7C%7C value.isEmpty()) ? defaultValue : value;%0A  %7D%0A%7D

Add get parameter function to utilities.