This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
The DOM and SAX APIs for XML parsing (part of J2SE 1.4) are not dependent on the existence of a DTD or XSD. In fact, I can't name a single parser that does require the document to be "validatable". Or did I misunderstood your question?