My xsd has a <xsd:attribute name="TS" type="xsd:dateTime" use="required" /> attribute. When I create my JaxB Java class it has a field called TS of type javax.xml.datatype.XMLGregorianCalendar; However when unmarsalling a xml file, I get the following error:

java.lang.NoClassDefFoundError: org/apache/xerces/jaxp/datatype/XMLGregorianCalendarImpl$Parser

Why would JaxB try to unmarshal to a different Object type?