code: public IMarshallingContext getMarshaller(String packageName, String bindingName) throws JiBXException
      {
          JIBXContextHolder jAXBContextHolder = this.get(packageName, bindingName);
          if (jAXBContextHolder == null)
              return null;    // Never
          return jAXBContextHolder.getMarshaller();
      }
docs: Get the shared unmarshaller for this context.
  NOTE: Since this is shared, always synchronize on this object.
  @param bindingName The JiBX binding name (defaults to 'binding')
  @return