Question about Barrier tutorial

[ChingShen]

Hi all,

  I run a Barrier example from ZooKeeper Tutorial(
http://zookeeper.apache.org/doc/r3.3.1/zookeeperTutorial.html#sc_barriers),
but I have a question about that does the example just enables a group of
processes to synchronize the beginning of a computation? does it not ensure
that the end of a computation? or is it a bug?

Thanks.

Shen