update log4j example (#13095)
update log4j example (#13095)

* update log4j example

* fix some style issues

* Update docs/configuration/logging.md

Co-authored-by: Frank Chen <b46d88371877ddcd44c759f0265b76c94e3085ba@apache.org>

Co-authored-by: Frank Chen <b46d88371877ddcd44c759f0265b76c94e3085ba@apache.org>
monetate/druid,monetate/druid,monetate/druid,monetate/druid,monetate/druid,monetate/druid,monetate/druid