IBM Support

IT18699: MQTT channel ends unexpectedly, and FDC with NullPointerException and Probe XR013012 is generated

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APAR status

  • Closed as program error.

Error description

  • The MQTT channel ends unexpectedly, and an FDC is generated with
    the details:
    
    | Probe Id          :- XR013012
    
    | Exception:1       :- java.lang.NullPointerException
    
    | Source            :-
    |
    |                   :- StateDump
    for:com.ibm.mq.communications.NonBlockingLis |
    |                   :- xxxxx@xxxxxx
    
    |   Throwable  :-
    |   |   Cause:1       :-  java.lang.NullPointerException
    |   |   StackTrace:1  :-  java.lang.NullPointerException
    |   |    at
    com.ibm.mq.communications.NonBlockingListener.run(NonBlockingLis
    tener.java:265)
    |   |    at java.lang.Thread.run(Thread.java:767)
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects users of:
    
    - The WebSphere MQ V7.5 MQXR service.
    - The IBM MQ V8.0 and V9.0 MQXR service.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    A MQTT client attempted to connect to the queue manager's
    telemetry (MQTT) channel. However, when the channel accepted the
    incoming server request there was an issue with it that meant
    that instead of a socket for that client being returned, a null
    object was instead. The attempt to use this when a socket was
    expected led to a NullPointerException, which caused the channel
    to end unexpectedly.
    

Problem conclusion

  • The case where accepting a client connection request returns a
    null rather than a socket is now handled appropriately, and the
    channel does not end. An entry will be appended to the mqxr.log
    file indicating an InvalidSelectionKeyException to notify that
    this error has occurred and to aid in further diagnosis if
    required. The messages written to the mqxr.log look like:
    
    9/11/17 16:19:42.515  AMQCO1002E: A selection
    key=sun.nio.ch.SelectionKeyImpl@f233874a was found in an
    unexpected state.
    
    The MQTT channel continues operation as normal.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v7.5       7.5.0.9
    v8.0       8.0.0.8
    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

    IT18699

  • Reported component name

    WMQ BASE MULTIP

  • Reported component ID

    5724H7241

  • Reported release

    750

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2017-01-06

  • Closed date

    2017-09-29

  • Last modified date

    2017-09-29

  • 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

    5724H7241

Applicable component levels

  • R750 PSY

       UP



Document information

More support for: WebSphere MQ
APAR / Maintenance

Software version: 7.5

Reference #: IT18699

Modified date: 29 September 2017


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