Hey,
I saw this issue #1370 and the following PR #1460.

But the problem is still not fixed on my Windows system. When I try to run ./gradlew build check I still get same error as in the issue reported.

Execution failed for task ':controlsfx:jar'.
> java.util.ConcurrentModificationException (no error message)

But after upgrading biz.aQute.bnd.builde to version 5.1.2 its now working. That was the same thing which @Maxoudela tried. But back then it seems that this was not working.