Github user MichaelScofield commented on the issue:
https://github.com/apache/zookeeper/pull/584
@anmolnar Thanks for the `computeIfAbsent` suggestion. Modified codes
accordingly.
@breed @lvfangmin I'm aware that `createNode` is single-threaded, and the
race condition I revealed is most likely not gonna happened in real world. But
the original codes already assumed a multi-threaded used ephemerals map, so I
think it's more reasonable to make it behaved more concurrency safe.---
