PH18777: CONCURRENTMODIFICATIONEXCEPTION AFTER PH07008

8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
9.0.5.3: WebSphere Application Server traditional Version 9.0.5 Fix Pack 3

APAR status

• Closed as program error.

Error description

• After applying PH07008 shipped by 8.5.5.16 (see TS002545981)
  customer experiences
  
  java.util.ConcurrentModificationException
   at
  java.util.HashMap$HashIterator.nextNode(HashMap.java:1456)
   at
  java.util.HashMap$KeyIterator.next(HashMap.java:1480)
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server - Java Persistence API - JPA 2.0 &   *
  *                  OpenJPA                                     *
  ****************************************************************
  * PROBLEM DESCRIPTION: OpenJPA's class metadata loading        *
  *                      could throw a                           *
  *                      ConcurrentModificationException. This   *
  *                      is a regression fix for PH18777.        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  There exists a narrow race condition during OpenJPA's class
  metadata loading in which multiple threads may attempt to
  access/modify the same Collection cache in OpenJPA's
  MetaDataRepository simultaneously. When this runtime exception
  occurs, a ConcurrentModificationException will be thrown. Due
  to OpenJPA's lazy metadata loading, this exception may be
  thrown well after an application has started and has been
  running. Reproducing the failure is very difficult as it
  requires hitting a narrow, multithreaded race condition.
  Exception:
  Caused by: java.util.ConcurrentModificationException
  at java.util.HashMap$HashIterator.nextNode(HashMap.java:1456)
  at java.util.HashMap$KeyIterator.next(HashMap.java:1480)
  at
  java.util.AbstractCollection.finishToArray(AbstractCollection.ja
  va:243)
  at
  java.util.AbstractCollection.toArray(AbstractCollection.java:210
  )
  at
  org.apache.openjpa.meta.MetaDataRepository.processRegisteredClas
  ses(MetaDataRepository.java:1638)
  at
  org.apache.openjpa.meta.ClassMetaData.getPCSubclasses(ClassMetaD
  ata.java:377)
  at
  org.apache.openjpa.meta.ClassMetaData.getPCSubclassMetaDatas(Cla
  ssMetaData.java:394)
  at
  org.apache.openjpa.meta.ClassMetaData.getMappedPCSubclassMetaDat
  as(ClassMetaData.java:416)
  at
  org.apache.openjpa.jdbc.meta.ClassMapping.getMappedPCSubclassMap
  pings(ClassMapping.java:655)
  at
  org.apache.openjpa.jdbc.meta.ClassMapping.getIndependentAssignab
  leMappings(ClassMapping.java:694)
  at
  org.apache.openjpa.jdbc.kernel.JDBCStoreManager.initializeState(
  JDBCStoreManager.java:344)
  at
  org.apache.openjpa.jdbc.kernel.JDBCStoreManager.initialize(JDBCS
  toreManager.java:306)
  at
  com.ibm.ws.persistence.jdbc.kernel.WsJpaJDBCStoreManager.initial
  ize(WsJpaJDBCStoreManager.java:178)
  at
  org.apache.openjpa.kernel.DelegatingStoreManager.initialize(Dele
  gatingStoreManager.java:112)
  at
  org.apache.openjpa.datacache.DataCacheStoreManager.initialize(Da
  taCacheStoreManager.java:360)
  at
  org.apache.openjpa.kernel.DelegatingStoreManager.initialize(Dele
  gatingStoreManager.java:112)
  at
  org.apache.openjpa.kernel.ROPStoreManager.initialize(ROPStoreMan
  ager.java:57)
  at
  org.apache.openjpa.kernel.BrokerImpl.initialize(BrokerImpl.java:
  1051)
  at
  com.ibm.ws.persistence.kernel.WsJpaBrokerImpl.initialize(WsJpaBr
  okerImpl.java:271)
  at
  org.apache.openjpa.kernel.BrokerImpl.find(BrokerImpl.java:1009)
  

Problem conclusion

• The fix for this APAR changes the OpenJPA implementation
  and involves an update to the third-party source. See
  https://issues.apache.org/jira/browse/OPENJPA-2767
  
  This fix is currently targeted for WebSphere Application
  Server 9.0.5.3, 8.5.5.17, and WebSphere Liberty 20.0.0.2.
  Please refer to the Recommended Updates
  page for delivery information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

Temporary fix

• Rerunning the operation seems to allow the exception to not
  occur again, but it may occur again in the future.
  

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

  WEBSPHERE FOR Z

• Fixed component ID

  5655I3500

Applicable component levels

• R850 PSY

     UP