private void initEmptyIterator() throws SQLException {
    try {
      fetchedRows = RowSetFactory.create(new TRowSet(), protocol);
      fetchedRowsItr = fetchedRows.iterator();
    } catch (TException e) {
      throw new SQLException(e);
    }
  }
Set the specified schema to the resultset
@param colNames
@param colTypes
jdbc/src/java/org/apache/hive/jdbc/HiveQueryResultSet.java