String json = "{"DATA":{"CAR_NO":123123},"USER_ID":300,"USER_NAME":"user1"}";
    ResultSet resultSet = null;
    long begin = System.currentTimeMillis();

    for (int j = 0; j < 1000; j++) {
        Statement statement = connection.createStatement();

        rootSchema.add("testDB", new JsonSchema("testTAB", json));

        resultSet = statement.executeQuery(
                "select * from "testDB"."testTAB" where USER_ID =300 order by USER_ID desc ");

        while (resultSet.next()) {
            JSONObject jo = new JSONObject();
            int n = resultSet.getMetaData().getColumnCount();
            for (int i = 1; i <= n; i++) {
                jo.put(resultSet.getMetaData().getColumnName(i), resultSet.getObject(i));
            }
        }

        resultSet.close();
        statement.close();
        connection.close();
    }

    System.out.println("Time elapsed:" + (System.currentTimeMillis() - begin));