$ zkCli -server 127.0.0.1:2181
Connecting to 127.0.0.1:2181
Welcome to ZooKeeper!
JLine support is enabled
[zk: 127.0.0.1:2181(CONNECTING) 0]
WATCHER::

WatchedEvent state:SyncConnected type:None path:null

[zk: 127.0.0.1:2181(CONNECTED) 0] ls /

WATCHER::

WatchedEvent state:Disconnected type:None path:null
Exception in thread "main" org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /
	at org.apache.zookeeper.KeeperException.create(KeeperException.java:90)
	at org.apache.zookeeper.KeeperException.create(KeeperException.java:42)
	at org.apache.zookeeper.ZooKeeper.getChildren(ZooKeeper.java:1243)
	at org.apache.zookeeper.ZooKeeper.getChildren(ZooKeeper.java:1271)
	at org.apache.zookeeper.ZooKeeperMain.processZKCmd(ZooKeeperMain.java:700)
	at org.apache.zookeeper.ZooKeeperMain.processCmd(ZooKeeperMain.java:581)
	at org.apache.zookeeper.ZooKeeperMain.executeLine(ZooKeeperMain.java:353)
	at org.apache.zookeeper.ZooKeeperMain.run(ZooKeeperMain.java:311)
	at org.apache.zookeeper.ZooKeeperMain.main(ZooKeeperMain.java:270)