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https://issues.apache.org/jira/browse/POOL-161?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mark Thomas updated POOL-161:
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    Fix Version/s: 1.5.8
    
> ContextClassLoader problems for the Evictor thread
> --------------------------------------------------
>
>                 Key: POOL-161
>                 URL: https://issues.apache.org/jira/browse/POOL-161
>             Project: Commons Pool
>          Issue Type: Bug
>    Affects Versions: 1.5.4
>            Reporter: Sylvain Laurent
>             Fix For: 1.6.1, 2.0, 1.5.8
>
>         Attachments: TestGenericObjectPoolClassLoader.patch.txt, 
> patch_Evictor_CCL.txt
>
>
> Since a single Timer is used for several GenericObjectPool instances, this 
> may create classloader issues and a memory leak of one classloader :
> Let's imagine the following scenario :
> - commons-pool.jar is in the classpath of a webapp container (e.g. tomcat).
> - 2 webapps A and B are deployed, each creating an instance of 
> GenericObjectPool for its own usage.
> - each webapp makes use of the idle object evictor and sets a positive number 
> for minIdle
> - first, webapp A instantiates its GenericObjectPool. Since this is the first 
> TimerTask to be created, the Timer instance is created, thus creating a 
> Thread whose ContextClassLoader is the current one, that is webapp A's 
> ContextClassLoader.
> The TimerTask properly creates instances of idle objects in the pool, making 
> use of the ObjectFactory provided by A.
> - then B instantiates its GenericObjectPool. A new TimerTask is created, and 
> it tries to invoke the ObjectFactory provided by B. But when it needs a class 
> that only exists in B webapp, it cannot find it because the 
> ContextClassLoader of the Timer Thread is A's classloader.
> Other side effect : if webapp A is undeployed, but B is still running, then 
> A's webappClassLoader cannot be GCed because the Timer Thread keeps a strong 
> reference to A's classloader (as its context classloader).

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