Out of sync on GAE


I’ve development a Vaadin GAE application. It’s work well when running in localhost but when deploy it to the appengine server it will get an ‘Out of sync’ error.
The log say, “com.vaadin.terminal.gwt.server.AbstractCommunicationManager handleVariableBurst: Warning: Ignoring variable change for non-existent component, VAR_PID=PID21”

Why this happen?


I have doing a mistake when creating a servlet that I use to extend ApplicationServlet

public class ExampleApplicationServlet extends ApplicationServlet {


after change to GAEApplicationServlet

public class ExampleApplicationServlet extends GAEApplicationServlet {


everything’s work fine.

Now my appengine running well on google.