[jira] [Resolved] (SLING-2743) Activator.getLoginModules in Jackrabbit server bundle should be synchronized

["Felix Meschberger (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SLING-2743?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Felix Meschberger resolved SLING-2743.
--------------------------------------

    Resolution: Won't Fix

As discussed: This is not needed (BundleActivators are called in controlled contexts by the framework) and dangerous for deadlocks (Framework holds lock when calling, the start method holds a lock when calling back into the framework).

Thus closing wontfix
                
> Activator.getLoginModules in Jackrabbit server bundle should be synchronized
> ----------------------------------------------------------------------------
>
>                 Key: SLING-2743
>                 URL: https://issues.apache.org/jira/browse/SLING-2743
>             Project: Sling
>          Issue Type: Bug
>          Components: JCR
>    Affects Versions: JCR Jackrabbit Server 2.1.0
>            Reporter: Ian Boston
>            Assignee: Ian Boston
>         Attachments: SLING-2743.patch
>
>
> Findbugs is reporting that the initialization of the static moduleCache, loginModuleTracker is unsafe in a threaded environment. The method should probably be synchronized to ensure that only one thread accesses the method at a time.
> FindBug Report:
> Bug: Incorrect lazy initialization and update of static field org.apache.sling.jcr.jackrabbit.server.impl.Activator.moduleCache in org.apache.sling.jcr.jackrabbit.server.impl.Activator.getLoginModules()
> This method contains an unsynchronized lazy initialization of a static field. After the field is set, the object stored into that location is further updated or accessed. The setting of the field is visible to other threads as soon as it is set. If the futher accesses in the method that set the field serve to initialize the object, then you have a very serious multithreading bug, unless something else prevents any other thread from accessing the stored object until it is fully initialized.
> Even if you feel confident that the method is never called by multiple threads, it might be better to not set the static field until the value you are setting it to is fully populated/initialized.
> Confidence: High, Rank: Scary (6)
> Pattern: LI_LAZY_INIT_UPDATE_STATIC 
> Type: LI, Category: MT_CORRECTNESS (Multithreaded correctness)

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