21 Dec 2017 15:25:59 [e88aa05a-c454-44c1-8e52-e7bd741a5df6] [pool-16-thread-1] WARN org.apache.lens.server.session.HiveSessionService - Unknown error while checking for inactive sessions -
java.lang.NullPointerException: null
at org.apache.lens.server.BaseLensService.decrementSessionCountForUser(BaseLensService.java:343) ~[classes/:na]
at org.apache.lens.server.BaseLensService.closeSession(BaseLensService.java:321) ~[classes/:na]
at org.apache.lens.server.session.HiveSessionService.closeInternal(HiveSessionService.java:497) ~[classes/:na]
at org.apache.lens.server.session.HiveSessionService.access$300(HiveSessionService.java:59) ~[classes/:na]
at org.apache.lens.server.session.HiveSessionService$SessionExpiryRunnable.runInternal(HiveSessionService.java:547) ~[classes/:na]
at org.apache.lens.server.session.HiveSessionService$SessionExpiryRunnable.run(HiveSessionService.java:569) ~[classes/:na]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_131]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_131]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_131]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Sche