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https://issues.apache.org/jira/browse/JCR-2768?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14302947#comment-14302947
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Konrad Windszus commented on JCR-2768:
--------------------------------------

Basically Jukka was already stating in the previous comment that relying on a 
WeakReference does not work. 
{quote}
Hmm, forget that, the reference is no longer available when a weak reference is 
enqueued.
{quote}

A similar approach with phantom references was also implemented for Sling 
Models to release the service references.

A more in depth comparison between phantom references and finalize can be found 
at http://java.dzone.com/articles/finalization-and-phantom.

> Finalize method on SessionImpl
> ------------------------------
>
>                 Key: JCR-2768
>                 URL: https://issues.apache.org/jira/browse/JCR-2768
>             Project: Jackrabbit Content Repository
>          Issue Type: Improvement
>          Components: jackrabbit-core
>    Affects Versions: 2.1
>            Reporter: Douglas Britsch
>
> Doing some profiling on our application which uses Jackrabbit-2.1.0 I noticed 
> that there were an awful lot of java.lang.ref.Finalizer objects hanging 
> around. Digging around I found the culprit was a finalize method on 
> SessionImpl. While I can see what it is trying to do (close the session if 
> you have not called logout) , I have found in the past that on application 
> servers, finalize should be avoided for objects that are created and deleted 
> frequently, as the GC behavior and object allocation is severely impacted, 
> and because of the number of references held by the session this seems like 
> it could keep a lot more in memory than needed a lot longer. (for more info 
> see http://www.fasterj.com/articles/finalizer1.shtml ).
> Per Jukka's suggestion on the mailing list "
> The automatic closing of a discarded session and related the warning
> message are pretty useful in practice, as there are quite a few
> session leaks in many client applications. So I'd rather keep that
> functionality.
> If the finalizer causes problems, we could investigate using weak (or
> perhaps phantom) references and a reference queue for this purpose.
> The RepositoryImpl class already keeps weak references to all sessions
> in the activeSessions map, so this shouldn't even be too difficult to
> implement."



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