[jira] [Commented] (TAP5-1557) ConcurrentModificationException in PersistentFieldManagerImpl

["Josh Canfield (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TAP5-1557?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13054968#comment-13054968 ] 

Josh Canfield commented on TAP5-1557:
-------------------------------------

Calls to Session.getAttributeNames is not thread safe in all application server session implementations.

The above exception looks like it's being run in Tomcat 5.5 because the session attributes are being stored in a Hashtable. In Tomcat 6 this should be gone because the session attributes are stores in an ConcurrentHashMap.

Jetty 7 is using a HashMap so it's probably still going to be a problem there.

AbstractSessionPersistentFieldStrategy uses getAttributeNames in two places which could possibly be removed by inspecting the page/components instead of the session.


> ConcurrentModificationException in PersistentFieldManagerImpl
> -------------------------------------------------------------
>
>                 Key: TAP5-1557
>                 URL: https://issues.apache.org/jira/browse/TAP5-1557
>             Project: Tapestry 5
>          Issue Type: Bug
>          Components: tapestry-core
>    Affects Versions: 5.3.0, 5.2.5
>            Reporter: Josh Canfield
>            Assignee: Josh Canfield
>
> Caused by: java.util.ConcurrentModificationException
>  at java.util.Hashtable$Enumerator.next(Hashtable.java:1031)
>  at org.apache.catalina.util.Enumerator.<init>(Enumerator.java:101)
>  at org.apache.catalina.util.Enumerator.<init>(Enumerator.java:67)
>  at org.apache.catalina.cluster.session.DeltaSession.getAttributeNames(DeltaSession.java:1046)
>  at org.apache.catalina.cluster.session.DeltaSessionFacade.getAttributeNames(DeltaSessionFacade.java:121)
>  at org.apache.tapestry5.internal.services.SessionImpl.getAttributeNames(SessionImpl.java:77)
>  at org.apache.tapestry5.internal.services.AbstractSessionPersistentFieldStrategy.gatherFieldChanges(AbstractSessionPersistentFieldStrategy.java:55)
>  at org.apache.tapestry5.internal.services.PersistentFieldManagerImpl.gatherChanges(PersistentFieldManagerImpl.java:62)
>  at $PersistentFieldManager_12fe8a643a9.gatherChanges($PersistentFieldManager_12fe8a643a9.java)
>  at org.apache.tapestry5.internal.structure.PageImpl.getFieldChange(PageImpl.java:206)
>  at org.apache.tapestry5.internal.structure.InternalComponentResourcesImpl.getFieldChange(InternalComponentResourcesImpl.java:176)
>  at org.apache.tapestry5.internal.structure.InternalComponentResourcesImpl.hasFieldChange(InternalComponentResourcesImpl.java:186)
>  at org.apache.tapestry5.internal.transform.PersistWorker$PersistentFieldConduit.restoreStateAtPageAttach(PersistWorker.java:80)
>  at org.apache.tapestry5.internal.transform.PersistWorker$PersistentFieldConduit.access$000(PersistWorker.java:38)
>  at org.apache.tapestry5.internal.transform.PersistWorker$PersistentFieldConduit$1.restoreStateBeforePageAttach(PersistWorker.java:61)
>  at org.apache.tapestry5.internal.structure.PageImpl.attached(PageImpl.java:184)
>  at org.apache.tapestry5.internal.services.NonPoolingRequestPageCacheImpl.get(NonPoolingRequestPageCacheImpl.java:78)

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