IBM Support

PM26342: Lock contention may occur with a JAX-RPC application when the BaseSerializerFactory uses Class.forName.

Fixes are available

6.1.0.37: Java SDK 1.5 SR12 FP3 Cumulative Fix for WebSphere
7.0.0.17: Java SDK 1.6 SR9 FP1 Cumulative Fix for WebSphere Application Server
6.1.0.47: WebSphere Application Server V6.1 Fix Pack 47
7.0.0.27: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
6.1.0.39: Java SDK 1.5 SR12 FP4 Cumulative Fix for WebSphere Application Server
6.1.0.41: Java SDK 1.5 SR12 FP5 Cumulative Fix for WebSphere Application Server
6.1.0.43: Java SDK 1.5 SR13 Cumulative Fix for WebSphere Application Server
6.1.0.45: Java SDK 1.5 SR14 Cumulative Fix for WebSphere Application Server
6.1.0.47: Java SDK 1.5 SR16 Cumulative Fix for WebSphere Application Server
7.0.0.19: Java SDK 1.6 SR9 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.21: Java SDK 1.6 SR9 FP2 Cumulative Fix for WebSphere
7.0.0.23: Java SDK 1.6 SR10 FP1 Cumulative Fix for WebSphere
7.0.0.25: Java SDK 1.6 SR11 Cumulative Fix for WebSphere Application Server
7.0.0.27: Java SDK 1.6 SR12 Cumulative Fix for WebSphere Application Server
7.0.0.29: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.45: Java SDK 1.6 SR16 FP60 Cumulative Fix for WebSphere Application Server
7.0.0.31: Java SDK 1.6 SR15 Cumulative Fix for WebSphere Application Server
7.0.0.35: Java SDK 1.6 SR16 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.37: Java SDK 1.6 SR16 FP3 Cumulative Fix for WebSphere Application Server
7.0.0.39: Java SDK 1.6 SR16 FP7 Cumulative Fix for WebSphere Application Server
7.0.0.41: Java SDK 1.6 SR16 FP20 Cumulative Fix for WebSphere Application Server
7.0.0.43: Java SDK 1.6 SR16 FP41 Cumulative Fix for WebSphere Application Server

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APAR status

  • Closed as program error.

Error description

  • Multiple threads may lock on the Class.forName code when
    running a JAX-RPC application.  These locks may reduce overall
    system throughput.
    
    Here is an example stack that may be seen within a javacore
    file:
    
    Java callstack:
    at java/lang/Class.forNameImpl(Native Method)
    at java/lang/Class.forName(Class.java:169)
    at
    com/ibm/ws/webservices/engine/utils/ClassUtils$2.run(ClassUtils.
    java:
    234)
    at
    java/security/AccessController.doPrivileged(AccessController.jav
    a:202
    )
    at
    com/ibm/ws/security/util/AccessController.doPrivileged(AccessCon
    troll
    er.java:61)
    at
    com/ibm/ws/webservices/engine/utils/ClassUtils.loadClass(ClassUt
    ils.j
    ava:210)
    at
    com/ibm/ws/webservices/engine/utils/ClassUtils.forName(ClassUtil
    s.jav
    a:136)
    at
    com/ibm/ws/webservices/engine/encoding/ser/BaseSerializerFactory
    $getS
    erializerMethodPRIV.run(BaseSerializerFactory.java:369)
    at
    java/security/AccessController.doPrivileged(AccessController.jav
    a:202
    )
    at
    com/ibm/ws/security/util/AccessController.doPrivileged(AccessCon
    troll
    er.java:61)
    at
    com/ibm/ws/webservices/engine/encoding/ser/BaseSerializerFactory
    .getS
    erializerMethod(BaseSerializerFactory.java:249)
    
    
    These threads are all trying to load a non-existent class
    "java/lang/String_Helper".
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  IBM WebSphere Application Server users or   *
    *                  administrators of JAX-RPC applications      *
    ****************************************************************
    * PROBLEM DESCRIPTION: Lock contention may occur with a        *
    *                      JAX-RPC application when the            *
    *                      BaseSerializerFactory uses              *
    *                      Class.forName.                          *
    ****************************************************************
    * RECOMMENDATION:  Install a fix pack containing this APAR.    *
    ****************************************************************
    Multiple threads may lock on the Class.forName code when
    running a JAX-RPC application.  These locks may reduce overall
    system throughput.
    
    Here is an example stack that may be seen within a javacore
    file:
    
    Java callstack:
    at java/lang/Class.forNameImpl(Native Method)
    at java/lang/Class.forName(Class.java:169)
    at
    com/ibm/ws/webservices/engine/utils/ClassUtils$2.run(ClassUtils.
    java:
    234)
    at
    java/security/AccessController.doPrivileged(AccessController.jav
    a:202
    )
    at
    com/ibm/ws/security/util/AccessController.doPrivileged(AccessCon
    troll
    er.java:61)
    at
    com/ibm/ws/webservices/engine/utils/ClassUtils.loadClass(ClassUt
    ils.j
    ava:210)
    at
    com/ibm/ws/webservices/engine/utils/ClassUtils.forName(ClassUtil
    s.jav
    a:136)
    at
    com/ibm/ws/webservices/engine/encoding/ser/BaseSerializerFactory
    $getS
    erializerMethodPRIV.run(BaseSerializerFactory.java:369)
    at
    java/security/AccessController.doPrivileged(AccessController.jav
    a:202
    )
    at
    com/ibm/ws/security/util/AccessController.doPrivileged(AccessCon
    troll
    er.java:61)
    at
    com/ibm/ws/webservices/engine/encoding/ser/BaseSerializerFactory
    .getS
    erializerMethod(BaseSerializerFactory.java:249)
    
    
    These threads are all trying to load a non-existent class
    "java/lang/String_Helper".
    

Problem conclusion

  • The JAX-RPC runtime loads _Helper classes to assist with the
    serialization and deserialization of the JAX-RPC data.
    
    There are some data types (for example, java.lang.String) that
    do not have _Helper classes.  The lock contention occurs while
    the JAX-RPC runtime searches for these non-existent _Helper
    classes.
    
    The JAX-RPC runtime is changed to avoid the _Helper class
    lookup for java.lang.String and other common data types.  This
    eliminates the lock contention.
    
    The fix for this APAR is currently targeted for inclusion in
    fix pack 7.0.0.17  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

    PM26342

  • Reported component name

    WEBS APP SERV N

  • Reported component ID

    5724H8800

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-11-09

  • Closed date

    2010-11-18

  • Last modified date

    2010-11-18

  • 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

    WEBS APP SERV N

  • Fixed component ID

    5724H8800

Applicable component levels

  • R700 PSY

       UP



Document information

More support for: WebSphere Application Server
General

Software version: 7.0

Reference #: PM26342

Modified date: 18 November 2010