IBM Support

IT31909: MQTT Channel ends unexpectedly due to NullPointerException

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APAR status

  • Closed as program error.

Error description

  • The MQTT channel ends with an error in the log:
    
    AMQCO2001E: An error (probe: XR014005) occurred and a Failure
    Data Capture (FDC) file has been written to file 'MQXR2.FDC'.
    AMQCO1006I: Channel 'XXXXXXXX' has stopped
    
    and an FDC generated with details:
    
     Probe Id          :- XR014005
    
     java.lang.NullPointerException
    at
    com.ibm.mq.MQXRService.MQTTServerSessionV3.handleReceive(MQTTSer
    verSessionV3.java:258)
    at
    com.ibm.mq.MQXRService.HttpServerContext.handleReceive(HttpServe
    rContext.java:235)
    at
    com.ibm.mq.MQXRService.HttpServerContext.handleWebSocketFrame(Ht
    tpServerContext.java:174)
    at
    com.ibm.mq.http.HttpWireContext.receiveWebsocketFrame(HttpWireCo
    ntext.java:563)
    at
    com.ibm.mq.http.HttpWireContext.receive(HttpWireContext.java:196
    )
    at
    com.ibm.mq.communications.NonBlockingConnection.receive(NonBlock
    ingConnection.java:386)
    at
    com.ibm.mq.communications.NonBlockingWorker.run(NonBlockingWorke
    r.java:398)
    at java.lang.Thread.run(Thread.java:818)
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects users of the MQTT channel service.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    The MQTT channel service may stop unexpectedly due to a
    NULLPOINTEREXCEPTION.  It will also generate a Failure Data
    Capture (FDC) file, which will contain the following java stack:
    
     java.lang.NullPointerException
       at
    com.ibm.mq.MQXRService.MQTTServerSessionV3.handleReceive(MQTTSer
    verSessionV3.java:258)
       at
    com.ibm.mq.MQXRService.HttpServerContext.handleReceive(HttpServe
    rContext.java:235)
       at
    com.ibm.mq.MQXRService.HttpServerContext.handleWebSocketFrame(Ht
    tpServerContext.java:174)
       at
    com.ibm.mq.http.HttpWireContext.receiveWebsocketFrame(HttpWireCo
    ntext.java:563)
       at
    com.ibm.mq.http.HttpWireContext.receive(HttpWireContext.java:196
    )
       at
    com.ibm.mq.communications.NonBlockingConnection.receive(NonBlock
    ingConnection.java:386)
       at
    com.ibm.mq.communications.NonBlockingWorker.run(NonBlockingWorke
    r.java:398)
       at java.lang.Thread.run(Thread.java:818)
    ```
    

Problem conclusion

  • The code has been changed to avoid this Null Pointer Exception
    and prevent the unexpected shutdown of the MQTT channel service
    for this particular issue.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.0 LTS   9.0.0.11
    v9.1 LTS   9.1.0.8
    v9.2 LTS   9.2.0.2
    
    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

    IT31909

  • Reported component name

    IBM MQ BASE MP

  • Reported component ID

    5724H7271

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-02-19

  • Closed date

    2020-10-13

  • Last modified date

    2020-10-13

  • 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

    IBM MQ BASE MP

  • Fixed component ID

    5724H7271

Applicable component levels

[{"Line of Business":{"code":"LOB36","label":"IBM Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"910"}]

Document Information

Modified date:
14 October 2020