We should replace c3p0 with [HikariCP|https://github.com/brettwooldridge/HikariCP]. HikariCP is much faster and less error prone. HikariCP is more popular with 13.2k+ stars on its github. There were no more new commits since Nov 18, 2019 in [c3p0|https://github.com/swaldman/c3p0/commits/master].
[MySQL connector|https://github.com/mysql/mysql-connector-j] should be upgraded to the latest stable versions as well to include many essential bugfixes.