JAXB dateTime xml marshal blank

Main.java


import java.io.StringWriter;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.GregorianCalendar;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.datatype.DatatypeConfigurationException;
import javax.xml.datatype.DatatypeConstants;
import javax.xml.datatype.DatatypeFactory;
import javax.xml.datatype.XMLGregorianCalendar;

public class Main {
    public static void main(String[] args){
        TheObject theObject = new TheObject();
        try {
            XMLGregorianCalendar dob = convertStringToXmlGregorian("2016-09-16");
            //should output this:
            /*
                <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
                <TheObject>
                    <DOB>2016-09-16</DOB>
                </TheObject>
            */
System.out.println(marshallTheObject(theObject));
        } catch (DatatypeConfigurationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JAXBException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    private static String marshallTheObject(TheObject theObject) throws JAXBException{
        JAXBContext jaxbContext = JAXBContext.newInstance(TheObject.class);
        Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
        jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        StringWriter sw = new StringWriter();
        jaxbMarshaller.marshal(theObject, sw);
        String output = sw.toString();
        return output;
    }
    private static XMLGregorianCalendar convertStringToXmlGregorian(String dateString)     throws DatatypeConfigurationException
    {
        try {
                SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
                java.util.Date date = sdf.parse(dateString);
                GregorianCalendar gc = (GregorianCalendar) GregorianCalendar.getInstance();
                gc.setTime(date);
                XMLGregorianCalendar calendar = DatatypeFactory.newInstance().newXMLGregorianCalendar(gc);
                calendar.setTimezone(DatatypeConstants.FIELD_UNDEFINED);
                calendar.setTime(DatatypeConstants.FIELD_UNDEFINED, DatatypeConstants.FIELD_UNDEFINED, DatatypeConstants.FIELD_UNDEFINED);
                return calendar;
            } catch (ParseException e) {
                e.printStackTrace();
                return null;
            }
    }
}




TheObject.java


import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlSchemaType;
import javax.xml.bind.annotation.XmlType;
import javax.xml.datatype.XMLGregorianCalendar;



@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "TheObject", propOrder = {
   "dob"
})
@XmlRootElement(name = "TheObject")
public class TheObject {


    @XmlElement(name = "DOB")
    @XmlSchemaType(name = "dateTime")
    protected XMLGregorianCalendar dob;
    /**
     * Gets the value of the dob property.
     *
     * @return
     *     possible object is
     *     {@link XMLGregorianCalendar }
     *
     */
    public XMLGregorianCalendar getDOB() {
        return dob;
    }

    /**
     * Sets the value of the dob property.
     *
     * @param value
     *     allowed object is
     *     {@link XMLGregorianCalendar }
     *
     */
    public void setDOB(XMLGregorianCalendar value) {
        this.dob = value;
    }


}