This week's book giveaways are in the Refactoring and Agile forums. We're giving away four copies each of Re-engineering Legacy Software and Docker in Action and have the authors on-line! See this thread and this one for details.
The data posted typically comes from a browser, and the browser doesn't know anything about 'objects'
It is possible to set up applet-servlet communication, but typically the objects are sent (via an object stream) to the client rather than the other way around. I see security issues in accepting object data from clients.