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https://issues.apache.org/jira/browse/OWB-1013?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14185208#comment-14185208
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Romain Manni-Bucau commented on OWB-1013:
-----------------------------------------

Hi

you put a stack by thread? Sounds wrong if you pass the instance between 
threads. In this case you should synchonize it yourself.

@everybody: why do we use a stack and not a linkedlist?

> Race condition in Instance injection
> ------------------------------------
>
>                 Key: OWB-1013
>                 URL: https://issues.apache.org/jira/browse/OWB-1013
>             Project: OpenWebBeans
>          Issue Type: Bug
>          Components: Injection and Lookup
>    Affects Versions: 1.2.6
>            Reporter: Tobias Stoeckmann
>            Assignee: Arne Limburg
>         Attachments: instance-race.zip, race.diff
>
>
> OpenWebBeans is prone to flip instances of javax.enterprise.inject.Instance 
> in multi-threaded environments.
> It is possible for multiple threads to access InstanceProducer at the same 
> time with the same creational context. If that happens, it is not verified 
> that these threads get the correct injectionPoint out of the injectionPoints 
> stack in the shared CreationalContextImpl.
> Please see attached example source (with comments included). It'll require a 
> debugger because it's quite tricky to get the threads into proper timing. 
> Start main method of class de.cewe.race.Main. It constructs a simple SE 
> container and executes two threads which will trigger the issue.
> Set breakpoints at:
> - de.cewe.race.CDIMain, line 46 (System.out.println)
> - org.apache.webbeans.portable.InstanceProducer, line 65 (getInjectionPoint)
> Wait until threads "RunnableA" and "RunnableB" reached the second breakpoint. 
> Then let RunnableA finish. It will trigger a ClassCastException. For your own 
> convenience, activate the second breakpoint after first one is reached. It 
> reduces debugger noise during startup.



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