How to debug JAXB unmarshalling?

I'm running into a problem with JAXB unmarshalling. I think I have it properly coded, but my unmarshalled object returns with null parameters. Consequently, I am assuming that when unmarshalling, JAXB is not seeing the appropriate XML structure that it is expecting. However, I do not get any error messages or any exceptions thrown.

Is there anyway to step through the unmarshalling process to see exactly where/why it is failing to populate my object(s)?

The actual unmarshalling code is fairly mundane:

public <T> T unmarshall(Node node, Class<T> clazz) throws JAXBException {
    // Creating an unmarshaller
    Unmarshaller u = JAXBContext.newInstance(clazz).createUnmarshaller();

    // unmarshal an instance node into  Java content
    return clazz.cast(u.unmarshal(node, clazz).getValue());
}

However, when I call it, I get an object of type clazz returned (as expected), but unpopulated.

The DOM object that I am trying to unmarshal is generated by a third party API. I have already run into some extremely odd behaviours with the unmarshalling, which is why I would like to be able to debug the process. For instance, if I try to unmarshal a sub-element within the DOM object (ie: doc.getByElementName("myElement").item(0)), it fails silently. However, if I convert the document to a string, and reimport it into a new document, then it converts it fine.

I am starting to get quite frustrated not knowing how to debug this issue.

Thanks for any insights!

Eric