Github user snuyanzin commented on the issue:
https://github.com/apache/flink/pull/6263
ok, thank you for review
about `public TemporaryFolder temporaryFolder = new TemporaryFolder();`
could be final - agree.
However while searching for usages I realized that in most cases it is not
final but not changed.
Am I right that in spite of existing code at least for newly created test
classes it is better to use temporaryFolder as final?---
