sending xml response from servlet

Hello,

Can someone recommend me a set of libraries that allow a servlet
receive/send XML documents from/to xforms? I have found several libraries,
but I don't know which is more adapted for what I want to do.

I'm using xforms in client side and a servlet for xindice (DB manager) calls
in server side.

The servlet gets the xml document from xforms and add it in the DB correctly
(I used a Xindice web application example and the tip 'Xforms tip: Accepting
XForms data in Java<http://www-128.ibm.com/developerworks/java/library/x-xformstipjava/index.html>'
for its construction), but I don't know how can I get a XML document from DB
and put it in the response object of the servlet.

The example of the tip works with strings, so following it for the response
I would have to take the XML document of the DB, transform it into a string,
and then send it. Cannot be the XML document sent as application/xml without
transforming it into a string?

Maybe questions are more java related than xforms, but they are
working-with-xml related so I think that I can found help in this forum.

Thanks
Iñaki