@jling, yes, I’m pre-allocating and even pre-processing strings before doing distance calculations. Actually the task is elementary. Simply speaking I have two lists of strings with ~10-30 characters. In the mentioned case with 10h x 60 threads it was 20k + 70k strings. And I’m using RatcliffObershelp() metrics for distance calculation. Even sorting of tokens I’m doing once for these stings. 60 threads are going through 20k list.
@jpsamaroo, thanks. It looks like I used old style but almost proper way how to fix it temporarily 
The task where I found the issue is a single run task. So, definitely I can check it with mentioned by you safepoint. At the same time I hope it will be fixed soon.