IT05296: WMQ 8.0 MQTT CHANNEL SUDDENLY STOPS WITH NULL POINTER EXCEPTIONS

Fix Pack 8.0.0.2 for WebSphere MQ V8.0

APAR status

• Closed as program error.

Error description

• With WebSphere MQ 8.0, MQTT channel stops to work suddenly. FDC
  files are generated with the following function stack:
  
  Cause:1 :- java.lang.NullPointerException
  StackTrace:1 :- java.lang.NullPointerException
      at
  com.ibm.mq.MQXRService.MQTTServerSession.scheduleAsynchronousWor
  k(MQTTServerSession.java:1567)
     at
  com.ibm.mq.MQXRService.MQTTServerSession.scheduleCompleteConnect
  ion(MQTTServerSession.java:1605)
     at
  com.ibm.mq.MQXRService.MQTTServerSession.doAsynchronousWork(MQTT
  ServerSession.java:1319)
     at
  com.ibm.mq.MQXRService.MQTTServerSessionV3.doAsynchronousWork(MQ
  TTServerSessionV3.java:1621)
     at
  com.ibm.mq.MQXRService.MQTTServerContext.doAsynchronousWork(MQTT
  ServerContext.java:191)
      at
  com.ibm.mq.communications.NonBlockingWorker.synchronousWorkCompl
  eted(NonBlockingWorker.java:633)
     at
  com.ibm.mq.communications.NonBlockingWorker.run(NonBlockingWorke
  r.java:421)
      at java.lang.Thread.run(Thread.java:804)
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of the WebSphere MQ MQXR service with
  large numbers of client performing connection takeovers.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  There was a timing issue where if a client with a specific ID
  reconnected from a different address, the takeover of the
  connection could fail due to there being a small timing window
  where an internal variable could be null.
  

Problem conclusion

• There is a check to confirm this internal variable is not null,
  and the NullPointerException does not occur.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.2
  
  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 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 MOBILITY

• Fixed component ID

  5724H7258

Applicable component levels

• R800 PSY

     UP