NPE during unlock operation --------------------------- Key: JGRP-2423 URL: https://issues.redhat.com/browse/JGRP-2423 Project: JGroups Issue Type: Bug Affects Versions: 4.1.8 Reporter: Max Shaposhnyk Assignee: Bela Ban Priority: Major Fix For: 4.1.9 The following NPE's are appearing in the che.openshift.io production server logs causing the multiple threads to blocking and break down some fuctionality. ATM we're unable to clearly reproduce issue on local installations (it happens very rarely on local, but quite frequently on prod server) {noformat} java.lang.NullPointerException: null at org.jgroups.util.Owner.compareTo(Owner.java:59) at org.jgroups.protocols.Locking$ClientLock.compareTo(Locking.java:1142) at org.jgroups.protocols.Locking$ClientLock.compareTo(Locking.java:942) at java.util.concurrent.ConcurrentSkipListMap.cpr(ConcurrentSkipListMap.java:655) at java.util.concurrent.ConcurrentSkipListMap.doPut(ConcurrentSkipListMap.java:835) at java.util.concurrent.ConcurrentSkipListMap.putIfAbsent(ConcurrentSkipListMap.java:1979) at java.util.concurrent.ConcurrentSkipListSet.add(ConcurrentSkipListSet.java:241) at org.jgroups.protocols.Locking$ClientLockTable.addToPendingReleaseRequests(Locking.java:1323) at org.jgroups.protocols.Locking$ClientLock._unlock(Locking.java:1070) at org.jgroups.protocols.Locking$ClientLock.unlock(Locking.java:996) at org.jgroups.protocols.Locking.down(Locking.java:176) at org.jgroups.stack.ProtocolStack.down(ProtocolStack.java:928) at org.jgroups.JChannel.down(JChannel.java:627) at org.jgroups.blocks.locking.LockService$LockImpl.unlock(LockService.java:167) at org.eclipse.che.multiuser.api.distributed.lock.JGroupsWorkspaceLockService$UnlockerImpl.unlock(JGroupsWorkspaceLockService.java:73) at org.eclipse.che.commons.lang.concurrent.Unlocker.close(Unlocker.java:38) at org.eclipse.che.api.workspace.server.WorkspaceRuntimes.$closeResource(WorkspaceRuntimes.java:314) {noformat} additional links: [1] https://github.com/eclipse/che/issues/15231 [2] https://issues.redhat.com/browse/JGRP-2299 [3] https://issues.redhat.com/browse/JGRP-2364 [4] https://github.com/eclipse/che/blob/master/assembly/assembly-wsmaster-war...