Can I unmarshall JSON without knowing which class to use?

[n***@public.gmane.org]

I have two methods that handle the different XML and JSON submissions
to our server. When using the json, I need to pass in the class while
JAXB handles figuring out which class. Is there a way to pass in the
class as part of the json submission?

protected Object unmarshallBeanXML (InputStream istrm)
throws Exception
{
Unmarshaller umarsh = jc.createUnmarshaller ();
return xmlcommand = umarsh.unmarshal (istrm);
}

protected Object unmarshallBeanJson (InputStream istrm, Class
clazz)
throws Exception
{
JSONUnmarshaller umarsh =
((JSONJAXBContext)jc).getJSONUnmarshaller(jc.createUnmarshaller ());
return umarsh.unmarshalFromJSON (istrm, clazz);
}

example jaxb class.

@XmlRootElement(name = "login")
public class Login {
}