docs: @Override
      public String[] findMemberGroupKeys(IEntityGroup group) throws GroupsException {
          Connection conn = null;
          Collection groupKeys = new ArrayList();
          String groupKey = null;
  
          try {
              conn = RDBMServices.getConnection();
              String sql = getFindMemberGroupKeysSql();
              PreparedStatement ps = conn.prepareStatement(sql);
              try {
                  ps.setString(1, group.getLocalKey());
                  if (LOG.isDebugEnabled())
                      LOG.debug(
                              "RDBMEntityGroupStore.findMemberGroupKeys(): "
                                      + ps
                                      + " ("
                                      + group.getLocalKey()
                                      + ")");
                  ResultSet rs = ps.executeQuery();
                  try {
                      while (rs.next()) {
                          groupKey = rs.getString(1) + groupNodeSeparator + rs.getString(2);
                          groupKeys.add(groupKey);
                      }
                  } finally {
                      rs.close();
                  }
              } finally {
                  ps.close();
              }
          } catch (Exception sqle) {
              LOG.error("RDBMEntityGroupStore.findMemberGroupKeys(): " + sqle);
              throw new GroupsException("Problem retrieving member group keys: " + sqle);
          } finally {
              RDBMServices.releaseConnection(conn);
          }
  
          return (String[]) groupKeys.toArray(new String[groupKeys.size()]);
      }