PI46699: A NULL VALUE IS RETURNED WHEN TRYING TO USE OPENJPA'S DELEGATINGCONNECTION'S UNWRAP()

8.5.5.9: WebSphere Application Server V8.5.5 Fix Pack 9
8.5.5.10: WebSphere Application Server V8.5.5 Fix Pack 10
8.5.5.11: WebSphere Application Server V8.5.5 Fix Pack 11
8.5.5.12: WebSphere Application Server V8.5.5 Fix Pack 12
8.5.5.13: WebSphere Application Server V8.5.5 Fix Pack 13
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
8.5.5.20: WebSphere Application Server V8.5.5.20
8.5.5.18: WebSphere Application Server V8.5.5 Fix Pack 18
8.5.5.19: WebSphere Application Server V8.5.5 Fix Pack 19
8.5.5.16: WebSphere Application Server V8.5.5 Fix Pack 16
8.5.5.21: WebSphere Application Server V8.5.5.21

APAR status

• Closed as program error.

Error description

• You may get a null value when trying to use OpenJPA's
  DelegatingConnection's unwrap() implementation.
  
  Looking at the contract for java.sql.Wrapper, which Connection
  implements, states:
  
  Returns an object that implements the given interface to allow
  access to non-standard methods, or standard methods not exposed
  by the proxy. If the receiver implements the interface then the
  result is the receiver or a proxy for the receiver. If the
  receiver is a wrapper and the wrapped object implements the
  interface then the result is the wrapped object or a proxy for
  the wrapped object. Otherwise return the the result of calling
  unwrap recursively on the wrapped object or a proxy for that
  result. If the receiver is not a wrapper and does not implement
  the interface, then an SQLException is thrown.
  
  OpenJPA's DelegatingConnection's unwrap() implementation checks
  if the type passed as the unwrap call's argument is
  type-compatible with the delegate, and if so, returns the
  Delegate - that part is consistent with the contract.  What's
  not consistent is when the delegate is not type-compatible with
  the argument - right now it returns null, when instead, as a
  wrapper object, it should be calling the delegate's unwrap()
  method and returning the result of that.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server Liberty Profile                      *
  ****************************************************************
  * PROBLEM DESCRIPTION: EntityManager.unwrap() with a           *
  *                      specific Connection implementation      *
  *                      class returns null.                     *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  OpenJPA's connection wrapper doesn't properly adhere to
  Connection.unwrap() contract.
  

Problem conclusion

• OpenJPA's DelegatingConnection class has been updated to
  properly adhere to the Connection.unwrap() contract, and will
  forward unwrap() invocations to the wrappered Connection for
  Class types it does not recognize.
  
  The fix for this APAR is currently targeted for inclusion in
  fix pack 8.5.5.9. 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

  LIBERTY PROFILE

• Fixed component ID

  5724J0814

Applicable component levels

• R850 PSY

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