IBM Support

PH26130: ADD PARALLEL CLASS LOADING SUPPORT TO WAS APPLICATION CLASS LOADERS

Subscribe to this APAR

By subscribing, you receive periodic emails alerting you to the status of the APAR, along with a link to the fix after it becomes available. You can track this item individually or track all items by product.

Notify me when this APAR changes.

Notify me when an APAR for this component changes.

 

APAR status

  • Closed as new function.

Error description

  • The WAS user-space class loaders (application, shared library,
    and extension class loaders) do not currently support the
    optional Java parallel class loading architecture, which allows
    classes of different names to be loaded simultaneously by a
    single class loader. Currently, the loadClass() method itself is
    synchronized in these loaders, so a class loader is locked by
    all class loads performed using it.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server                                      *
    ****************************************************************
    * PROBLEM DESCRIPTION: WAS class loaders do not support        *
    *                      parallel                                *
    *                      class loading                           *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    Java 7 modified the ClassLoader.loadClass() API to include
    optional support for parallel class loading, removing the
    synchronization from the loadClass() method and instead locking
    on a combination of the class loader and the class being loaded,
    allowing multiple threads to simultaneously use the same class
    loader. WAS' application and server level loaders did not
    implement this optional behavior, which could lead to increased
    contention and performance issues in environments where multiple
    threads were attempting to load classes using the same class
    loader.
    

Problem conclusion

  • Server class loaders have been updated to support Java parallel
    class loading.
    
    The fix for this APAR is targeted for inclusion in fix pack
    9.0.5.6. For more information, see 'Recommended Updates for
    WebSphere Application Server':
    https://www.ibm.com/support/pages/node/715553
    

Temporary fix

Comments

APAR Information

  • APAR number

    PH26130

  • Reported component name

    WEBSPHERE APP S

  • Reported component ID

    5724J0800

  • Reported release

    900

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-06-08

  • Closed date

    2020-11-24

  • Last modified date

    2020-11-24

  • 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

[{"Line of Business":{"code":"LOB36","label":"IBM Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"900"}]

Document Information

Modified date:
25 November 2020