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PI63178: HUNG THREADS OR INFINITE LOOP ON STARTUP IN WEAKHASHMAP.GETENTRY

Fixes are available

9.0.0.2: WebSphere Application Server traditional V9.0 Fix Pack 2
8.5.5.11: WebSphere Application Server V8.5.5 Fix Pack 11
9.0.0.3: WebSphere Application Server traditional V9.0 Fix Pack 3
9.0.0.4: WebSphere Application Server traditional V9.0 Fix Pack 4
8.5.5.12: WebSphere Application Server V8.5.5 Fix Pack 12
9.0.0.5: WebSphere Application Server traditional V9.0 Fix Pack 5
9.0.0.6: WebSphere Application Server traditional V9.0 Fix Pack 6
8.5.5.13: WebSphere Application Server V8.5.5 Fix Pack 13
9.0.0.7: WebSphere Application Server traditional V9.0 Fix Pack 7
9.0.0.8: WebSphere Application Server traditional V9.0 Fix Pack 8
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
9.0.0.9: WebSphere Application Server traditional V9.0 Fix Pack 9
9.0.0.10: WebSphere Application Server traditional V9.0 Fix Pack 10
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
9.0.0.11: WebSphere Application Server traditional V9.0 Fix Pack 11
9.0.5.0: WebSphere Application Server traditional Version 9.0.5 Refresh Pack
9.0.5.1: WebSphere Application Server traditional Version 9.0.5 Fix Pack 1
9.0.5.2: WebSphere Application Server traditional Version 9.0.5 Fix Pack 2
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
9.0.5.4: WebSphere Application Server traditional Version 9.0.5 Fix Pack 4
9.0.5.5: WebSphere Application Server traditional Version 9.0.5 Fix Pack 5
9.0.5.6: WebSphere Application Server traditional Version 9.0.5 Fix Pack 6

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APAR status

  • Closed as program error.

Error description

  • The non synchronized access from AjTypeSystem.getAjType(clazz)
    to a static instance of WeakHashMap may cause an infinite loop
    at start up in a multi threaded system.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server V8.5.5 and V9.0, that deploy         *
    *                  applications that use AspectJ:              *
    *                  Aspect-Oriented Programming extensions for  *
    *                  Java.                                       *
    ****************************************************************
    * PROBLEM DESCRIPTION: There is high CPU usage or the system   *
    *                      hangs, when the WebSphere Application   *
    *                      Server starts up. The server stops      *
    *                      taking transactions due to all of the   *
    *                      WebContainer threads being consumed.    *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    When applications that use AspectJ contain non-thread safe
    Hashmap usage, it may cause the system to hang at server
    startup. The non synchronised access from
    AjTypeSystem.getAjType(clazz) to a static instance of
    WeakHashMap may cause an infinite loop at start up in a multi
    threaded system. This is a known AspectJ issue.
    

Problem conclusion

  • To prevent the system hang and high CPU usage on server
    startup, the AspectJ (aspectjrt.jar) version was updated to
    1.6.4, which resolved the issue.
    
    The fix for this APAR is currently targeted for inclusion in
    fix packs 8.5.5.11 and 9.0.0.2. Please refer to the
    Recommended Updates page for delivery information:
    http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
    

Temporary fix

Comments

APAR Information

  • APAR number

    PI63178

  • Reported component name

    WEBSPHERE APP S

  • Reported component ID

    5724J0800

  • Reported release

    850

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-05-26

  • Closed date

    2016-08-30

  • Last modified date

    2016-08-30

  • 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 APP S

  • Fixed component ID

    5724J0800

Applicable component levels

  • R850 PSY

       UP

  • R900 PSY

       UP

[{"Business Unit":{"code":"BU053","label":"Cloud \u0026 Data Platform"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"850","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
14 October 2021