Bumps [mysql-connector-java](https://github.com/mysql/mysql-connector-j) from 5.1.46 to 8.0.16.
- [Release notes](https://github.com/mysql/mysql-connector-j/releases)
- [Changelog](https://github.com/mysql/mysql-connector-j/blob/release/8.0/CHANGES)
- [Commits](https://github.com/mysql/mysql-connector-j/compare/5.1.46...8.0.16)

add @Override

fix bug for log; adjust the order of object creation to avoid creating useless objects

1. if `filteredNotifications` is not empty, then  `namespaces` will not empty。 so check  `filteredNotifications` before  `namespaces ` Initialized ， will avoid create useless object

2. constructor （for set and map ）: choose more appropriate initialCapacity

avoid creating useless objects

the detail function is "findByUserIds(List<String> userIds)"

sql(apollo-portal): apollo.portal.meta.servers