Github user bowenli86 commented on the issue:
https://github.com/apache/flink/pull/5820
@zentol which scala checkstyle mvn plugin are you looking at? I didn't find
any available ones, and I'm afraid there might will not be one.
scalastyle explicitly said that they will not support capturing unused
imports at https://github.com/scalastyle/scalastyle/issues/193---
