[jbossws-issues] [JBoss JIRA] Commented: (JBWS-2317) $JAXBAccessorF_ and $JAXBAccessorM_ cache loosing classes and failing to re-create classes.

[Alessio Soldano (JIRA)]

    [ https://issues.jboss.org/browse/JBWS-2317?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12605239#comment-12605239 ] 

Alessio Soldano commented on JBWS-2317:
---------------------------------------

Richard, thanks for the comment. Can you verify if the problem is gone with jbossws 3.4.x ? We're using JAXB 2.2 since 3.4.x, so assuming the jaxb fix went upstream too at Sun/Oracle, this jira could be solved.

> $JAXBAccessorF_ and $JAXBAccessorM_ cache loosing classes and failing to re-create classes.
> -------------------------------------------------------------------------------------------
>
>                 Key: JBWS-2317
>                 URL: https://issues.jboss.org/browse/JBWS-2317
>             Project: JBoss Web Services
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>          Components: jbossws-metro, jbossws-native
>    Affects Versions:  jbossws-native-3.0.3,  jbossws-metro-3.0.3
>            Reporter: Darran Lofthouse
>            Assignee: Alessio Soldano
>         Attachments: Injector.java
>
>
> The JAXB implementation contains a package of classes to optimise field and method access by dynamically generating classes to avoid reflection, this has a start-up performance hit but then leads to an optimised runtime.
> The package is: -
>   'com.sun.xml.bind.v2.runtime.reflect.opt'
> Within the Injector class is a HashMap to maintain a cache of these classes against the classloader they were created for: -
> private static final Map<ClassLoader,WeakReference<Injector>> injectors =
>        Collections.synchronizedMap(new WeakHashMap<ClassLoader,WeakReference<Injector>>());
> A WeakReference has been used to wrap the value to prevent the value retaining a reference to the ClassLoader and then preventing garbage collection and leading to a leak.
> The problem is that nothing retains a reference to the Injector so as this is wrapped with a WeakReference it is garbage collected.
> I will attach to this case a new version of Injector.java.
> The fix switches to using a Strong reference to the Injector so it is not garbage collected.
> To maintain the original requirements the Injector will no longer hold a reference to the ClassLoader and will instead make use of the one passed in.  
> Within the Injector the HashMap of classes will reference the Class with a WeakReference.  If we get a WeakReference with no class it means the class was previously loaded but garbage collected, in this case try to load the class by name from the classloader - if this fails then redefine the class.

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