PM15029: INVOKING AN XSLT, XPATH OR XQUERY EXECUTABLE THE FIRST TIME IN MULTI-THREADED PROGRAM MAY CAUSE ARRAYINDEXOUTOFBOUNDSEXCEPTION

APAR status

• Closed as program error.

Error description

• If a multi-threaded program creates XExecutable objects for one
  or more XSLT stylesheets, XQuery expressions or XPath, and two
  or more threads invoke any of the execute methods of those
  XExecutable objects for the first time at nearly the same time,
  an ArrayIndexOutOfBoundsException may be reported for one of the
  calls to an execute method.  All subsequent processing will
  proceed successfully.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of the IBM WebSphere Application  *
  *                  Server v7.0 Feature Pack for XML 1.0.       *
  ****************************************************************
  * PROBLEM DESCRIPTION: If an application prepares one or more  *
  *                      XExecutable objects for XSLT            *
  *                      stylesheets, XQuery expressions or      *
  *                      XPath expressions, and then the         *
  *                      application attempts to invoke an       *
  *                      execute method of one or more of those  *
  *                      XExecutable objects on more than one    *
  *                      thread, an                              *
  *                      ArrayIndexOutOfBoundsException might be *
  *                      thrown for one of the threads.  All     *
  *                      subsequent attempts to call execute     *
  *                      methods will succeed.                   *
  *                                                              *
  *                      The same symptoms might occur on the    *
  *                      first invocation of the                 *
  *                      XItemFactory.item(Source) method if     *
  *                      more than one thread in an application  *
  *                      attempts to invoke that method.         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The IBM WebSphere Application Server Feature Pack for
  XML supports input from StreamSource, DOMSource, SAXSource or
  StAXSource objects.  It has several different "data adapters"
  that each support one or more of these forms of input.  When
  a Source object is first supplied on the execute method of an
  XExecutable object or on the item(Source) method of an
  XItemFactory object, the Feature Pack for XML initializes an
  array containing internal descriptions of the data adapters and
  the forms of input Source objects each is able to process.
  The Feature Pack for XML will then select the data adapter from
  the array that is best suited to process the particular Source
  object that was supplied on the XExecutable.execute method or
  the XItemFactory.item(Source) method, and identifies that data
  adapter by way of the index for that data adapter's array entry.
  
  It is possible for two threads to attempt to access that array
  for the first time at nearly the same time, for one thread to
  begin initializing the array and the second thread to begin
  accessing the incompletely initialized array.  In accessing
  the incompletely initialized array, the second thread might
  fail to find a data adapter entry in the array that is
  suitable for processing the Source object.  This is indicated
  with an invalid array index of -1, which triggers an
  ArrayIndexOutOfBoundsException.
  
  In the meanwhile, the first thread completes initializing the
  array of data adapters, and all subsequent attempts to find the
  data adapter best-suited to a particular Source object succeed.
  

Problem conclusion

• The problem was resolved by adding synchronization to the
  method that initializes the array of data adapters.  When that
  method is invoked on a particular thread, no other thread is
  permitted to enter the method until all entries in the array
  have been completely initialized.  That ensures that no other
  thread accesses the incompletely initialized array, and so
  ensures that every attempt to identify a data adapter that is
  best-suited to a particular Source object succeeds.
  
  The fix for this APAR is currently targeted for inclusion in
  fix pack 1.0.0.7. Please refer to the Recommended Updates
  page for delivery information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

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

  XML FEATUREPACK

• Fixed component ID

  5724J0856

Applicable component levels

• R700 PSY

     UP