I'm aware of a few frameworks (e.g., struts) that provide validation for web forms. Actually, they perform client and server side validation for fields within the form. Are there any such frameworks that exist within the Swing world?
W3C is working on an XForms standard (see this description and the 1.0 draft) that allows form validation and can be used for both web based and Swing (or any other client GUI toolkit) form validation.
I found this implementation which focusses on web forms so it might not be that useful in your case. I'm sure there are a couple of implementations out there or being developed that I missed, so search the net! :-)