PI05377: Websphere eXtreme scale receives a ConcurrentModificationException exception and route table

APAR status

• Closed as program error.

Error description

• WebSphere eXtreme Scale servers or clients receive a
  ConcurrentModificationException in the logs and FFDCs, and
  events are not delivered in a timely fashion.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  WebSphere eXtreme Scale users of            *
  *                  statistics monitoring or data               *
  *                  grids that are configured with a            *
  *                  PER_CONTAINER                               *
  *                  placementStrategy setting.                  *
  ****************************************************************
  * PROBLEM DESCRIPTION: An occasional                           *
  *                      ConcurrentModificationException         *
  *                      exception                               *
  *                      occurs and a routing update is delayed. *
  *                      The problem corrects itself.            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  WebSphere eXtreme Scale servers or clients receive a
  ConcurrentModificationException exception in the logs and first-
  failure data capture (FFDC) log. Event delivery is delayed.
  An example of the exception follows:
  Stack Dump = java.util.ConcurrentModificationException
  at java.util.HashMap$HashIterator.nextEntry(HashMap.java:905)
  at java.util.HashMap$EntryIterator.next(HashMap.java:945)
  at java.util.HashMap$EntryIterator.next(HashMap.java:943)
  at
  com.ibm.ws.objectgrid.corba.cluster.ClusterStore$RouteTableRetri
  ever.updateListeners(ClusterStore.java:874)
  at
  com.ibm.ws.objectgrid.corba.cluster.ClusterStore$RouteTableRetri
  ever.access$1100(ClusterStore.java:108)
  at
  com.ibm.ws.objectgrid.corba.cluster.ClusterStore$RouteTableRetri
  ever$SessionHandlerListerUpdater.processListenerEvents(ClusterSt
  ore.java:1150)
  at
  com.ibm.ws.objectgrid.corba.cluster.ClusterStore$RouteTableRetri
  ever$SessionHandlerListerUpdater.run(ClusterStore.java:1098)
  at java.lang.Thread.run(Thread.java:780)
  

Problem conclusion

• The locking behavior of the ClusterStore class was modified,
  correcting the ConcurrentModificationException exception
  condition.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WS EXTREME SCAL

• Fixed component ID

  5724X6702

Applicable component levels

• R860 PSY

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