IC88691: WEBSPHERE MQ .NET APPLICATION WITH CLIENT AUTOMATIC RECONNECT ENABLED THROWS A NULLREFERENCEEXCEPTION DURING RECONNECT

WebSphere MQ V7.5 Fix Pack 7.5.0.1
Fix Pack 7.1.0.3 for WebSphere MQ V7.1

APAR status

• Closed as program error.

Error description

• When using WebSphere MQ .Net application with client automatic
  reconnection enabled, after a broken connection a
  NullReferenceException is thrown during a reconnection attempt.
  
  XMS trace shows NullReferenceException is thrown from Reconnect
  method:
  
  [16/11/2012 20:40:57:339933 ] 00000011 d UOW=
  source=IBM.WMQ.Nmqi.MQManagedReconnectableThread Exception in
  method Run()
  [16/11/2012 20:40:57:339933 ] 00000011 X UOW=
  source=IBM.WMQ.Nmqi.MQManagedReconnectableThread
  System.NullReferenceException: Object reference not set to an
  instance of an object.
  at
  IBM.WMQ.Nmqi.MQManagedReconnectableThread.Reconnect
  (ManagedHconn remoteHconn)
  at IBM.WMQ.Nmqi.MQManagedReconnectableThread.Run()
  [16/11/2012 20:40:57:371183 ] 00000011 > UOW=
  source=IBM.WMQ.Nmqi.MQManagedReconnectableThread
  method=FFST(String,string,string,uint,uint,MQULONG,MQULONG,
  ushort)
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of the WebSphere MQ .Net application
  where client automatic reconnect functionality has been enabled.
  
  Platforms affected:
  Windows
  
  ****************************************************************
  PROBLEM SUMMARY:
  When WebSphere MQ .Net application is enabled with client
  automatic reconnection and a remote connection has been broken
  before any asynchronous messaging had occurred, waking the
  dispatcher thread that handles asynchronous message consumption
  results in NullReferenceException as this thread would not have
  been created.
  

Problem conclusion

• The code has been altered to ensure the asynchronous message
  consume dispatch thread has been created prior to the broken
  connect, waking it only in the case it exists. This change
  prevents the NullReferenceException from occurring.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
                     v7.1
  Platform           Fix Pack 7.1.0.3
  --------           --------------------
  Windows            7.1.0.3
  
  Platform           v7.5
  --------           --------------------
  Multiplatforms     7.5.0.1
  
  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 WINDOWS V7

• Fixed component ID

  5724H7220

Applicable component levels

• R710 PSY

     UP