code: public void preDelete(Group group) throws Exception
     {
        String groupId = null;
        if (group.getId() != null)
        {
           groupId = group.getId();
        }
        else
        {
           String parentId = group.getParentId();
           if (parentId == null || parentId.length() == 0)
              groupId = "/" + group.getGroupName();
           else
              groupId = parentId + "/" + group.getGroupName();
        }
        removeGroup(jcrService_.getCurrentRepository(), groupId);
     }
docs: {@inheritDoc}