code: @Group
     public final String getGroup()
     {
        if (fullGroupName != null)
        {
           return fullGroupName;
        }
        StringBuilder sb = new StringBuilder();
        if (ownerId != null)
        {
           sb.append(ownerId).append('-');
        }
        return fullGroupName = sb.append(group == null ? id : group).toString();
     }
docs: This method is used for the grouping when its enabled. It will return
  the value of the group if it has been explicitly set otherwise it will
  return the value of the fullId
  @return the group