IT46018: MQHeaderList.write() does not correctly format header(s) whencalled with a specific CCSID and a "raw" OutputStream.

APAR status

• Closed as program error.

Error description

• An MQHeaderList (and therefore the MQHeader object(s) that it
  encapsulates) can be written to an MQMessage object. This is the
  typical use case. When MQHeaderList.write() is called in this
  way the MQMD (and the CCSID field it encapsulates) of the
  MQMessage is used to determine the character encoding of the
  message content.
  
  MQHeaderList.write() can also be called on a Java
  DataOutputStream object. This use case is typically utilised to
  "build" an MQMessage object from individual headers. When called
  in this manner the write() method is not correctly utilising the
  CCSID field on the write() method call. Instead it is treating
  the DataOutputStream as an MQMessage, attempting to read its
  MQMD (headers) and failing. When failing it resorts to using the
  platform specific default CCSID.
  
  This ultimately results in the underlying bytes being
  incorrectly encoded if the CCSID specified in the call to
  write() is not the same as the platform default.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects IBM MQ Java applications that are "building"
  messages specifying individual header(s) and calling
  MQHeaderList.write() to write those header(s) to an underlying
  DataOutputStream object.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  An MQHeaderList (and therefore the MQHeader object(s) that it
  encapsulates) can be written to an MQMessage object. This is the
  typical use case. When MQHeaderList.write() is called in this
  way the MQMD (and the CCSID field it encapsulates) of the
  MQMessage is used to determine the character encoding of the
  message content.
  
  MQHeaderList.write() can also be called on a Java
  DataOutputStream object (as opposed to the aforementioned
  MQMessage object). This use case is typically utilised to
  "build" an MQMessage object from individual headers. When called
  in this manner the write() method was not correctly utilising
  the CCSID field on the write() method call. Instead it treated
  the DataOutputStream as an MQMessage, attempting to read its
  MQMD and failing. This casued it to resort to using the platform
  specific default CCSID, rather than the one passed in on the
  write() call.
  
  Lets assume an example for the latter use case. For the sake of
  the below example accept that, at the time of this APAR
  publication, CCSID 1208 is synonymous with UTF-8 and CCSID 1390
  is synonymous with Japan EBCDIC and the byte representations may
  change.
  
  Running on a platform where the default CCSID is 1208, the
  application created a new MQHeader object of type MQIIH. The
  application now attempted to write this MQHeader (by calling
  MQHeaderList.write() after MQHeaderList.add()) with characters
  encoded in CCSID 1390.
  
  When the write() call returned, and the underlying
  DataOutputStream has been written to, looking at the bytes it
  could be seen that the character "I" was encoded as byte 0x49
  (as specified in 1208) instead of 0xC9 (as specified in 1390)
  and spaces were encoded as byte 0x20 (1208) instead of 0x40
  (1390).
  
  This meant that the underlying bytes, which would most likely be
  used to create an MQMessage object for transmission, contained
  incorrectly encoded bytes. This could cause unexpected behaviour
  on the receiving application.
  
  This APAR is applicable to any combination of supported CCSID's
  where MQHeaderList.write() is being called requesting a CCSID
  that is not the calling platforms' default.
  

Problem conclusion

• Calling MQHeaderList.write() will now correctly write headers to
  underlying objects not of type MQMessage.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.3 LTS   9.3.0.25
  v9.4 LTS   9.4.0.5
  v9.x CD    9.4.1
  
  The latest available maintenance can be obtained from
  'IBM MQ Recommended Fixes'
  https://www.ibm.com/support/pages/recommended-fixes-ibm-mq
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'IBM MQ
  Planned Maintenance Release Dates'
  https://ibm.biz/mqplannedmaintenance
  
  ---------------------------------------------------------------
  

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

  MQ BASE V9.3

• Fixed component ID

  5724H7291

Applicable component levels