private void add(User parentResource, Map<String, Object> propertyMap) {
   String qualifiedName = (String) propertyMap.get("qualifiedName");
   Class<UserGroup> baseTumlClass = UmlgSchemaFactory.getUmlgSchemaMap().get(qualifiedName);
   try {
     Object id = propertyMap.get("id");
     UserGroup childResource = UMLG.get().getEntity(id);
     parentResource.addToUsergroup(childResource);
     childResource.fromJson(propertyMap);
   } catch (Exception e) {
     throw new RuntimeException(e);
   }
 }
 private void put(Map<String, Object> propertyMap) {
   Object id = propertyMap.get("id");
   UserGroup childResource = UMLG.get().getEntity(id);
   childResource.fromJson(propertyMap);
   Class<? extends UserGroup> baseTumlClass = childResource.getClass();
 }