Ajax and Vaadin

Hi all,
I’m newcomer in Vaadin :slight_smile:
I’would like to achieve something quite simple but I’m sticked with it.
I started from the Vaadin example (click on the button and there is a message)
I replace some of the coe inside the cliklistener for doing this stuff:
making a request to a Google Service, which send me back a json stream.
I can do that, but I have some Warning when I launch the soft (through Tomcat). Problem with serialization.
Things come bad when I had a simple Jackson Factory to deserialize the json.
Is there something wrong in the way I did ?
(I mean not in the code but in the way to achieve this task in Vaadin)
Thanks for your help