Communication problem, UIDL could not be read from server, error 404


I have deployed a few Vaadin portlets 6.7.8 on Liferay 6.1.0. If I load the portal in the browser as first page one with Vaadin portlets, I always get this error, but if I load first another page and then navigate to a page with Vaadin portlets, there is no problem. This doesn’t happen with a local server.

In my opinion, the portal session needs some time to get everything ready and everything downloaded to the browser. So, when the 1st page (no portal page previously loaded in the browser) has Vaadin portlets, they try to initialize themselves and use not ready resources.

This sample portlet fails

public class Test2Application extends Application {

	public void init() {
		Window window = new Window();


		Label label = new Label("Hello Test2!");



I’ve added a logger and I see init() is executed OK. The error happens after init().

Any ideas?

I’m getting the same problem using vaadin 6.8.4 and Tomcat 7.0.
In the past the application didn’t give this error with previous version of vaadin.
Recently I have got to change the UI with a more intensive use of Window and I also have updated the vaadin jar.

Have you solved your issue ? or anyone have a suggestion ?


Problem solved. It was a mistake of Eclipse that do not deploy correctly the application.