code: private static String stripRealm(String uniqueUserId, String realm) {
          if (uniqueUserId == null || realm == null)
              return uniqueUserId;
          int index = uniqueUserId.indexOf(realm + REALM_SEPARATOR);
          if (index > -1) {
              uniqueUserId = uniqueUserId.substring(index + realm.length() + 1);
          }
          return uniqueUserId;
      }
docs: Some registries return user:realm/uniqueId on the invocation of the getUniqueUserId
  method but do not accept it as the uniqueUserId for other methods like getUniqueGroupIds.
  This method is used to strip of the user:realm/ portion and get the uniqueId
  
  @param uniqueUserId The uniqueId of the user
  @param realm The realm that this uniqueId belongs to
  @return the uniqueUserId with the realm stripped off.