Minor Description
A log statement should be guarded by its matching severity level. A log statement like
if (LOG.isTraceEnabled()) {
LOG.debug(identifier + " opening connection to ZooKeeper ensemble=" + ensemble);
doesn't make much sense because the log message is only printed out when TRACE-level is enabled. This inconsistency was possibly introduced when developers demoted the original log statement from DEBUG but forgot to change its corresponding log severity level.