UnmarshalException：XML上的意外元素只是Marshaller

解组XML时遇到了UnmarshalException（意外元素），而我刚通过marshaller运行过。我看起来像编组过程生成XML，不能将其解组。

ObjectFactory objectFactory = new ObjectFactory();
EjendomSoegType type = objectFactory.createEjendomSoegType();
EjendomSoegningKriterierType krit = new EjendomSoegningKriterierType();
{
    krit.setBy("Skovlunde");
}
type.setEjendomSoegningKriterier(krit);
JAXBElement<EjendomSoegType> soeg = objectFactory.createEjendomSoeg(type);

// create JAXBContext which will be used to update writer
JAXBContext context = JAXBContext.newInstance(EjendomSoegType.class);

// marshall or convert jaxbElement containing element to xml format
Marshaller marshaller = context.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
StringWriter writer = new StringWriter();
marshaller.marshal(soeg, writer);

String xml = writer.toString();
System.out.println( xml );

Unmarshaller unmarshaller = context.createUnmarshaller();
StringReader reader = new StringReader(xml);
soeg = (JAXBElement<EjendomSoegType>) unmarshaller.unmarshal(reader);

代码unmarshaller.unmarshal（reader）的最后一行引发以下UnmarshalException ：

javax.xml.bind.UnmarshalException: unexpected element (uri:"http://rep.oio.dk/tinglysning.dk/service/message/elektroniskakt/1/", local:"EjendomSoeg"). Expected elements are (none)
     at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(UnmarshallingContext.java:609)
     at com.sun.xml.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:244)

生成的XML看起来像：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns8:EjendomSoeg xmlns:ns2="http://rep.oio.dk/tinglysning.dk/schema/model/1/" 
        xmlns:ns4="http://rep.oio.dk/cpr.dk/xml/schemas/core/2005/03/18/" 
        xmlns:ns3="http://rep.oio.dk/kms.dk/xml/schemas/2005/03/11/" 
        xmlns:ns5="http://rep.oio.dk/bbr.dk/xml/schemas/2005/03/11/" 
        xmlns:ns6="http://rep.oio.dk/bbr.dk/xml/schemas/2005/12/15/" 
        xmlns:ns7="http://rep.oio.dk/tinglysning.dk/schema/elektroniskakt/1/" 
        xmlns:ns8="http://rep.oio.dk/tinglysning.dk/service/message/elektroniskakt/1/">
    <ns7:EjendomSoegningKriterier>
        <By>Skovlunde</By>
    </ns7:EjendomSoegningKriterier>
</ns8:EjendomSoeg>

为什么会引发UnmarshalException？

其他信息：ObjectFactory中的createEjendomSoeg方法具有@XmlElementDecl标记。

/**
 * Create an instance of {@link JAXBElement }{@code <}{@link EjendomSoegType }{@code >}}
 * 
 */
@XmlElementDecl(namespace = "http://rep.oio.dk/tinglysning.dk/service/message/elektroniskakt/1/", name = "EjendomSoeg")
public JAXBElement<EjendomSoegType> createEjendomSoeg(EjendomSoegType value) {
    return new JAXBElement<EjendomSoegType>(_EjendomSoeg_QNAME, EjendomSoegType.class, null, value);
}