ZOOKEEPER-850 added slf4j to ZK. We still depend on log4j in our codebase. We should remove the dependency on log4j so that we can make logging pluggable.
Migrate to Log4J 2.
Switch from log4j to slf4j
Revert run-time dependency on log4j and slf4j-log4j12
Unable to eliminate log4j1 transitive dependency