Java EE (Java Enterprise Edition) General Discussion

I am doing some integration with a third-party. The project involves sending an XML request, receiving a response, parsing, and displaying the results in a browser. I have received DTDs from the third party, and must validate the request before the message is sent (posted) from my side. However, the third party requires that a <!DOCTYPE> declaration should not exist in the document. Can someone give me an example of how to validate an XML document with no <!DOCTYPE>? I am building the document object with JDOM. Also, any suggestions on a parser implementation?

Thanks,

Ben