We publish an XML doclet at:
http://www.sun.com/xml/developers/doclet
However, it is not complete in that it does not generate a serialized form specification.
We are considering releasing another XML doclet that is complete, then writing an XSLT
translation to DocBook, or SolBook (Sun's version). However, this is not a high priority
and may take a year or longer.
-Doug Kramer
Javadoc team