Integrate Extjs on frontend and Tapestry on backend

I had a开发者_如何学C project that requires the use of Extjs as the frontend of my program and tapestry on the backend.

I am new with both, but still able to create the panels of forms on the frontend, however can anyone advise how would it be possible to link/integrate with the backend java side of tapestry such that the Extjs form panel would update the json data based from my backend?

Thanks.

Take a loot at the HowTos and this wiki entry is a good starting point