Usage of javax.xml.datatype.XMLGregorianCalendar.toGregorianCalendar()

import javax.xml.datatype.DatatypeFactory;
import javax.xml.datatype.XMLGregorianCalendar;

XMLGregorianCalendar dateDemande =
DatatypeFactory.newInstance().newXMLGregorianCalendar(2012, 5, 23, 12,
        22, 00, 00, 1);

Customizations for WCF Service WSDL with Java client

http://docs.oracle.com/cd/E17802_01/webservices/webservices/reference/tutorials/wsit/doc/DataBinding5.html#wp98106