While running builds I noticed the following warning from Maven..

XMLGregorianCalendarImpl is internal proprietary API and 
may be removed in a future release 

Rightfully so if you’re not using the correct convention for this..

type.setDate(new XMLGregorianCalendarImpl());

A quick look at Stackoverflow shows this: http://stackoverflow.com/a/5402007/1410035

In short you need to leverage a factory pattern and get an instance of the underlying implementation. The following snippet is an example of this:

import javax.xml.datatype.XMLGregorianCalendar;
import javax.xml.datatype.DatatypeFactory;
import java.util.GregorianCalendar;
private XMLGregorianCalendar now;

now = DatatypeFactory.newInstance().newXMLGregorianCalendar(new GregorianCalendar());

And your code will be in better shape and future-proofed as well.