I'm not aware of any relevant existing base class in the Derby test framework for running multi-threaded tests.
I think that the classes and infrastructure in o.a.derbyTesting.perf.clients have much to offer. They are not JUnit test cases, but they have a lot of support for defining workloads, and managing threads, and tracking increments and timings.
They are really more suited for running benchmarks, but hopefully there is a lot of re-usable code there for developing concurrent tests. thanks, bryan
