To implement data access code in our application we need some framework to wrap around jdbc (ORM is not our choice, because of scalability).
The coolest framework I
mJDBC: https://mjdbc.github.io/
I use it for years and found it very useful.
It is inspired by JDBI library but has no dependencies, adds transactions support, provides performance counters and allows to switch to the lowest possible SQL level in Java (old plain JDBC API) easily in case if you really need it.