IBM Support

IT19024: NullPointerException in ServerWorker thread and Telemetry service ends

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APAR status

  • Closed as program error.

Error description

  • NullPointerException causes the IBM MQ Telemetry service to end,
    disconnecting
    all connected clients. An FDC is generated with following
    symptom:
    
    Thread          :- name=ServerWorker0 priority=5 group=main
                       ccl=sun.misc.Launcher$AppClassLoader@ca2651dc
    Source Class    :- com.ibm.mq.communications.NonBlockingWorker
    Source Method   :- run
    Probe Id        :- XR014005
    FileInformation :- C:\ProgramData\IBM\MQ\errors\MQXRxxx.FDC
    Suppressed Count:- 0
    JavaDump file   :- null
    Thread          :- ServerWorker0
    Mem Max/Free/Tot:- xxxxxxxx / xxxxxxx / xxxxxxxx
    Loaded from     :-
                      jar:file:/C:/ibm/mq/mqxr/lib/MQXRListener.jar!
                  /com/ibm/mq/communications/NonBlockingWorker.class
    ----------------------------------------------------------------
    java.lang.NullPointerException
    at com.ibm.mq.MQXRService.MQSubscriptionWrapper.subWithOptions
      (MQSubscriptionWrapper.java:340)
    at
    com.ibm.mq.MQXRService.MQSubscriptionWrapper.doNextRemainingWork
      (MQSubscriptionWrapper.java:658)
    at com.ibm.mq.MQXRService.MQTTServerSession.doFollowOnWork
      (MQTTServerSession.java:1515)
    at com.ibm.mq.MQXRService.WorkerContext.doFollowOnWork
      (WorkerContext.java:669)
    at com.ibm.mq.MQXRService.WorkerContext.synchronousWorkCompleted
      (WorkerContext.java:326)
    at
    com.ibm.mq.communications.NonBlockingWorker.synchronousWorkCompl
      eted(NonBlockingWorker.java:620)
    at com.ibm.mq.communications.NonBlockingWorker.run
      (NonBlockingWorker.java:422)
    at java.lang.Thread.run(Thread.java:809)
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects users connecting to the queue manager's MQTT
    channel and making subscriptions.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    There was a small timing window where if a subscription request
    being made for a MQTT client coincided with the connection
    closing, a subscription request was made on the closed
    connection object, intermittently resulting in a
    NullPointerException. This exception caused the MQTT service to
    end.
    

Problem conclusion

  • The timing window where the NullPointerException could occur has
    been removed, and the exception no longer occurs.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v8.0       8.0.0.9
    v9.0 LTS   9.0.0.3
    
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT19024

  • Reported component name

    WMQ BASE MULTIP

  • Reported component ID

    5724H7251

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2017-01-30

  • Closed date

    2017-11-28

  • Last modified date

    2017-11-28

  • 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

    WMQ BASE MULTIP

  • Fixed component ID

    5724H7251

Applicable component levels

  • R800 PSY

       UP

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Document Information

Modified date:
28 November 2017