Recently, NIFI-6360  was resolved with PR 3533  merged to master.
All NiFi components were upgraded to use Mockito version 2.28.2, including
updating those components to use mockito-core instead of mockito-all since
the mockito-all distribution was discontinued in Mockito 2.
The Mockito dependency upgrade was one of several PRs (with a few more on
the way) needed to support building NiFi on Java 11.
For those of you with PRs open that reference Mockito, please rebase onto
the current master. If you have specific issues with the Mockito upgrade,
I'd be happy to help you resolve them.