[jQuery] Best practice for integrating server-side validation (jsp) with jquery validation (specially bassistance)

[jQuery] Best practice for integrating server-side validation (jsp) with jquery validation (specially bassistance)

Hi All,
I was wondering if there is a link or pointers for best practices while integrating client side validation errors with server side validation. I read on a forum that this requires the server side to return a json, but could not find many pointers or details about this.
Can somebody please provide some tips on how best to achieve this? By the way I am using the bassistance plugin, my application is a legacy app written in jsp & is database intensive; And so far I have not considered using ajaxform etc..<br clear="all">
Thanks,
Anoop