Estou usando o Xstream para serializar um objeto Job. Parece estar funcionando be

mas desserializando, estou com um problema:

Exception in thread "main" com.thoughtworks.xstream.io.StreamException:  : only whitespace content allowed before start tag and not . (position: START_DOCUMENT seen .... @1:1) 
    at com.thoughtworks.xstream.io.xml.XppReader.pullNextEvent(XppReader.java:78)
    at com.thoughtworks.xstream.io.xml.AbstractPullReader.readRealEvent(AbstractPullReader.java:137)
    at com.thoughtworks.xstream.io.xml.AbstractPullReader.readEvent(AbstractPullReader.java:130)
    at com.thoughtworks.xstream.io.xml.AbstractPullReader.move(AbstractPullReader.java:109)
    at com.thoughtworks.xstream.io.xml.AbstractPullReader.moveDown(AbstractPullReader.java:94)
    at com.thoughtworks.xstream.io.xml.XppReader.<init>(XppReader.java:48)
    at com.thoughtworks.xstream.io.xml.XppDriver.createReader(XppDriver.java:44)
    at com.thoughtworks.xstream.XStream.fromXML(XStream.java:853)
    at com.thoughtworks.xstream.XStream.fromXML(XStream.java:845)

Algum de vocês já teve esse problema antes?

Este é o caminho que fiz para serializar:

XStream xstream = new XStream();                    
Writer writer = new FileWriter(new File("model.xml"));
writer.write(xstream.toXML(myModel));
writer.close();

Eu também tento isso também:

XStream xstream = new XStream();                    
OutputStream out = new FileOutputStream("model.xml");
xstream.toXML(myModel, out);

Para desserializar, eu fiz assim:

XStream xstream = new XStream();

xstream.fromXML("model.xml");

strutura @XML:

<projectCar.CarImpl> 
   <CarModel reference="../.."></CarModel>
</projectCar.CarImpl> 

Se sim, eu gostaria de ouvir. Desde já, obrigado