code: private Object refObj(Object obj, XmlParser.Node node) throws NoSuchMethodException,
              ClassNotFoundException, InvocationTargetException, IllegalAccessException
      {
          String id = node.getAttribute("id");
          obj = _idMap.get(id);
          if (obj == null) throw new IllegalStateException("No object for id=" + id);
          configure(obj, node, 0);
          return obj;
      }
docs: /*
  Reference an id value object.
  
  @param obj @param node @return @exception NoSuchMethodException @exception
  ClassNotFoundException @exception InvocationTargetException