Set tagsets = new HashSet();
    static Set /* <Long> */ getDistinctTagsets(Connection conn, int mailboxId)    throws ServiceException {        PreparedStatement stmt = null;        ResultSet rs = null;        Set tagsets = new HashSet();                try {            stmt = conn.prepareStatement("SELECT DISTINCT tags " +                "FROM " + DbMailItem.getMailItemTableName(mailboxId));            rs = stmt.executeQuery();            while (rs.next()) {                long tags = rs.getLong(1);                tagsets.add(new Long(tags));            }        } catch (SQLException e) {            throw ServiceException.FAILURE("getting distinct tagsets", e);        } finally {            DbPool.closeResults(rs);            DbPool.closeStatement(stmt);        }        return tagsets;    }