IBM Support

PH05787: CONCURRENTMODIFICATIONEXCEPTION

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • ConcurrentModificationException happens when a web
    application
    receives a large number of requests immediately after it
    starts.
    
    
    Caused by: java.util.ConcurrentModificationException
    at
    java.util.ArrayList$Itr.checkForComodification(ArrayList.jav
    a:91
    2)
    at java.util.ArrayList$Itr.next(ArrayList.java:862)
    at
    com.ibm.ws.webcontainer.util.MetaInfResourcesFileUtils.<init
    >(Me
    taInfResourcesFileUtils.java:81)
    at
    com.ibm.ws.webcontainer.util.DocumentRootUtils.getMetaInfRes
    (Doc
    umentRootUtils.java:492)
    at
    com.ibm.ws.webcontainer.util.DocumentRootUtils.handleDocumen
    tRoo
    ts(DocumentRootUtils.java:204)
    at
    com.ibm.ws.webcontainer.util.DocumentRootUtils.handleDocumen
    tRoo
    ts(DocumentRootUtils.java:171)
    at
    com.ibm.ws.webcontainer.osgi.webapp.WebApp.getResourceAsStre
    am(W
    ebApp.java:544)
    at
    com.ibm.wsspi.webcontainer.facade.ServletContextFacade.getRe
    sour
    ceAsStream(ServletContextFacade.java:158)
    ... 105 more
    
    Problem first reported on Liberty 17.0.0.3 and also
    recreated
    on 18.0.0.3
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server Liberty                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: ConcurrentModificationException might   *
    *                      occur with a large number of requests   *
    *                      immediately after application is        *
    *                      started.                                *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    If a large number of concurrent requests run immediately after
    an application is started, there is a chance that a
    java.util.ConcurrentModificationException will occur that will
    fail all future requests until the application is restarted.
    
    Here is an example of the stack trace for this issue, which can
    be seen in messages.log:
    
    Caused by: java.util.ConcurrentModificationException
    at
    java.util.ArrayList$Itr.checkForComodification(ArrayList.java:91
    2)
    at java.util.ArrayList$Itr.next(ArrayList.java:862)
    at
    com.ibm.ws.webcontainer.util.MetaInfResourcesFileUtils.(MetaInfR
    esourcesFileUtils.java:81)
    at
    com.ibm.ws.webcontainer.util.DocumentRootUtils.getMetaInfRes(Doc
    umentRootUtils.java:492)
    at
    com.ibm.ws.webcontainer.util.DocumentRootUtils.handleDocumentRoo
    ts(DocumentRootUtils.java:204)
    at
    com.ibm.ws.webcontainer.util.DocumentRootUtils.handleDocumentRoo
    ts(DocumentRootUtils.java:171)
    at
    com.ibm.ws.webcontainer.osgi.webapp.WebApp.getResourceAsStream(W
    ebApp.java:544)
    at
    com.ibm.wsspi.webcontainer.facade.ServletContextFacade.getResour
    ceAsStream(ServletContextFacade.java:158)
    

Problem conclusion

  • The web container was modified to correctly handle the resources
    list that led to the ConcurrentModificationException.
    
    The fix for this APAR is currently targeted for inclusion in fix
    pack 19.0.0.1.  Please refer to the Recommended Updates page for
    delivery information:
    http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
    

Temporary fix

  • Restart the application.
    

Comments

APAR Information

  • APAR number

    PH05787

  • Reported component name

    WAS LIBERTY COR

  • Reported component ID

    5725L2900

  • Reported release

    855

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2018-11-27

  • Closed date

    2019-02-05

  • Last modified date

    2019-02-05

  • 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

    WAS LIBERTY COR

  • Fixed component ID

    5725L2900

Applicable component levels

  • R855 PSY

       UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSD28V","label":"WebSphere Application Server Liberty Core"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"855","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
17 October 2021