IJ40117: AOT COMPILED METHOD CAUSES CRASH OR UNEXPECTED OUTPUT

APAR status

• Closed as program error.

Error description

• Error Message: The JVM will likely crash with a GPF, but it may
  be possible in some cases for execution to continue with
  incorrect output.
  .
  Stack Trace: No specific stack trace, but detailed corefile
  analysis will implicate an AOT loaded method body. The only
  known case to date involved the apache http client library and
  the problem method was
  {org/apache/http/client/methods/HttpRequestBase.getURI()Ljava/ne
  t/URI;}
  .
  

Local fix

• The problem can be avoided by disabling AOT using the command
  line option
  -Xnoaot
  Disabling AOT completely with the above option will cause the
  JVM startup to take a little longer. If it can be determined
  which method is causing the problem then just that method can be
  targeted using
  -Xaot:loadExclude={a/b/ExampleClass.exampleMethod(*}
  

Problem summary

• This problem occurs when two or more copies of a class hierarchy
  are present in the shared class cache, as can happen when
  applications depend on different versions of a library, and
  those different versions have a different number of fields in
  one of the ancestors in the hierarchy. In this scenario the
  lookup mechanism to locate an AOT method body in the shared
  class cache fails to correctly identify the correct method to
  match the classes being used.
  

Problem conclusion

• The AOT method lookup implementation has been modified to
  unambiguously confirm that the method body matches the class for
  which the method is being requested.
  See OpenJ9 PR
  https://github.com/eclipse-openj9/openj9/pull/15037 and it's
  associated issue for further technical details.
  .
  This APAR will be fixed in the following Releases:
  .
  IBM SDK, Java Technology Edition
     8    SR7 FP15  (8.0.7.15)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  maintenance can be found at:
             https://www.ibm.com/support/pages/java-sdk
  

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

  JIT

• Fixed component ID

  620700124

Applicable component levels