做某国企项目(分内网、外网交换网)，应用在交换网，数据库在内网，应用不能直接访问内网数据库，只能通过安全隔离网闸访问内网数据库，安全隔离网闸(相当于数据库代理)提供了一个驱动包。出现了如下的错误，也不影响后续操作，异常如下：
2019-03-21 14:46:22.037 WARN com.alibaba.druid.pool.DruidConnectionHolder:121 [RMI TCP Connection(3)-127.0.0.1] - getHoldability unsupported
java.lang.UnsupportedOperationException: null
at sgcc.nds.jdbc.driver.NdsConnection.getHoldability(NdsConnection.java:991) ~[SqlProxyCfg_Jdbc-20171130.jar:?]
at com.alibaba.druid.pool.DruidConnectionHolder.(DruidConnectionHolder.java:118) [druid-1.1.12.jar:1.1.12]
at com.alibaba.druid.pool.DruidConnectionHolder.(DruidConnectionHolder.java:75) [druid-1.1.12.jar:1.1.12]
at com.alibaba.druid.pool.DruidDataSource.init(DruidDataSource.java:875) [druid-1.1.12.jar:1.1.12]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_40]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_40]