https://community.cloudera.com/t5/Support-Questions/Receiving-ZooKeeperException-when-trying-connect-to-Solr/m-p/53445#M19189 It is closing the session and then trying to use it again. The close is outside of the main class (I don't know if it was extracted from somewhere else). Also what is 'zk'? You are checking if it null and closing if it is but I don't see it declared anywhere in the code you posted.<BR /><BR />2017-04-06 13:33:19,353 DEBUG main.close - Closing session: 0x15ad7740271bb85<BR />2017-04-06 13:33:19,354 DEBUG main.close - Closing client for session: 0x15ad7740271bb85<BR />2017-04-06 13:33:19,362 DEBUG main-SendThread(dwh-mst-dev01.stor.nccourts.org:2181).readResponse - Reading reply sessionid:0x15ad7740271bb85, packet:: clientPath:null serverPath:null finished:false header:: 4,-11 replyHeader:: 4,55835606664,0 request:: null response:: null Mon, 10 Apr 2017 22:25:03 GMT mbigelow 2017-04-10T22:25:03Z