code: public static IEntityGroup getRootGroup(Class<?> type) throws GroupsException {
          LOGGER.trace("Invoking getRootGroup for type='{}'", type);
          return instance().igetRootGroup(type);
      }
docs: Refers to the PropertiesManager to get the key for the root group associated with 'type' and
  asks the group store implementation for the corresponding <code>IEntityGroup</code>.