Java: How to use a DTD inside an XML document when processing it with Java?

I have an xml file which I am trying to process with Java. It turned out I needed a DTD for my XML document because I had non-xml standard entities in my xml document.

So my question is how do I process an xml file with Java while making it aware that there is a DTD embedded into th开发者_如何学编程e XML document?

Thanks,

Take a look at the EntityResolver: http://www.ibm.com/developerworks/library/x-tipent.html