Brian DePradine created OPENJPA-2222:
----------------------------------------
Summary: Concurrency issue with JPA enhancement in Apache Open JPA
Key: OPENJPA-2222
URL: https://issues.apache.org/jira/browse/OPENJPA-2222
Project: OpenJPA
Issue Type: Bug
Components: Enhance
Affects Versions: 2.2.0
Reporter: Brian DePradine
Working Jeremy Bauer, we discovered the following issue:
I think I've figured out what is causing the transformer to return null in some
(intermittent) cases. I'm seeing multiple threads [Blueprint Extender: # ]
calling into the same PCClassFileTransformer. I've pasted the stack for thread
1 below. I saw an identical instance for a thread 3 - operating on a different
persistent class at the same time. This resulted in one of the transforms
(per transform method below) returned null.
public byte[] transform(ClassLoader loader, String className,
Class redef, ProtectionDomain domain, byte[] bytes)
throws IllegalClassFormatException {
if (loader == _tmpLoader)
return null;
// JDK bug -- OPENJPA-1676
if (className == null) {
return null;
}
---------------------
// prevent re-entrant calls, which can occur if the enhancing
// loader is used to also load OpenJPA libraries; this is to prevent
// recursive enhancement attempts for internal openjpa libraries
if (_transforming)
return null;
---------------------
_transforming = true;
return transform0(className, redef, bytes);
}
Since you use the same transformer on multiple threads we are hitting the
condition where there is a transform in progress and you are trying to do
another transform on a separate thread.
I spent some time looking at the JPA spec to determine what it says about
transformer concurrency and I can't find anything that says that you shouldn't
be able to call a transformer in a concurrent manner, hence this defect.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
