Github user ijokarumawak commented on the issue:
https://github.com/apache/nifi/pull/2510
@mcgilman Thanks for clarifying the String manipulation exception, I just
didn't have enough imagination to come up with such invalid inputs. I switched
to use regex to check and parse property keys. Now it should be more robust and
provide more user friendly error messages.
Also, added try/catch for EL parse failure. Thanks!---
