Vaadin Validation


Im in the process of converting my existing Swing based product into the vaadin based SPA webui. I gone through the tutorials and i made lot of Vaadin UI examples equivalent to my existing Swing components.
But i have a question on how the event handing is done in Vaddin. The reason is that in my Swing application all the jars are downloaded into my client and all the validatation happens at the client side. For example i have two dependent tables if i delete a particular entry i had to delete the record from the other table first and delete the current one. These two tables are in the different Panels in swing. In Vaadin its going to be in a different View. But im wondering the validation has to go to the server ?. If all the validation requests has to go to the server my client wont accept the solution. I’m sure Vaadin framework must be having different approach but i couldn’t get it through the tutorials or i may be missing something basic here. Can you please provide me how the validation is done, is each validation requests hit server?