@Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // super.doPost(req, resp); DatastoreService datastore = DatastoreServiceFactory.getDatastoreService(); Gson gson = new Gson(); Plan pl = gson.fromJson(req.getParameter("PARAM"), Plan.class); Entity plan = new Entity("Plan"); plan.setProperty("title", pl.getTitle()); plan.setProperty("description", pl.getDesc()); plan.setProperty("domain", pl.getDomain()); plan.setProperty("totalLength", pl.getTotalTime()); System.out.println(pl.getTotalTime()); Key planKey = datastore.put(plan); List<Exercise> listEx = pl.getExercises(); Entity exercise; for (Exercise ex : listEx) { exercise = new Entity("Exercise", planKey); exercise.setProperty("title", ex.getTitle()); exercise.setProperty("description", ex.getDesc()); String length = ex.getLength(); String[] splitStr = length.split(":"); Integer seconds = Integer.parseInt(splitStr[0]) * 60 + Integer.parseInt(splitStr[1]); exercise.setProperty("length", seconds); exercise.setProperty("row", ex.getRow()); datastore.put(exercise); } }