mysql 8.0 or above, mysql-connector-java.jar must also be 8.0 or above, c3p0 server version 9.5.4 or 9.5.2
but,
It is recommended that you install mysql version 5.5. Recently, you have encountered too many problems that the version does not correspond to or problems that the version is too high.
Compared with MySQL 8.0 and above, no one may have encountered a problem before, so there will be few solutions. MySQL5.5 version is more stable.
You can download it on the official website by yourself. Baidu search, mysql5.5 download