[weld-issues] [JBoss JIRA] Commented: (WELD-920) Memory leak through the creational context of an @AppScoped bean when injecting Instance<>

[Joshua Davis (JIRA)]

    [ https://issues.jboss.org/browse/WELD-920?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12614242#comment-12614242 ] 

Joshua Davis commented on WELD-920:
-----------------------------------

Now that I understand this a little better, I like the idea of analyzing the dependent instance graph and not tracking (managing) any instances that don't have @PreDestroy/@Disposer methods.   It _should_ be a fully transparent optimization.

+1 on putting a *big warning* in the docs about Instance<>, as this has tripped up a bunch of people so far.


> Memory leak through the creational context of an @AppScoped bean when injecting Instance<>
> ------------------------------------------------------------------------------------------
>
>                 Key: WELD-920
>                 URL: https://issues.jboss.org/browse/WELD-920
>             Project: Weld
>          Issue Type: Bug
>          Components: Scopes & Contexts
>    Affects Versions: 1.1.0.CR3, 1.1.1.Final
>            Reporter: Adam Warski
>         Attachments: leak-test-1.war, leak-test.tar.gz
>
>
> Given a simple dependent-scoped bean: public class InstanceBean {}, and an application-scoped bean (see below) to which an instance of the dependent-scoped bean is injected, each time the get() method is called on the instance, even though it's not used, a reference to it stays in the creational context of the application scoped bean (http://screencast.com/t/XqjQ1GB7Wv3). That way after several requests, where each one calls the method, more and more memory is leaked (http://screencast.com/t/s1VBx49i).
> Attached is a simple web application demonstrating this. To reproduce, deploy to AS6, click the "leak" button several times, and analyze the heap dump e.g. in JProfiler.
> @ApplicationScoped
> @Named("test")
> public class AppScopedBean {
>     private Instance<InstanceBean> instanceBeanInstance;
>     @Inject
>     public AppScopedBean(Instance<InstanceBean> instanceBeanInstance) {
>         this.instanceBeanInstance = instanceBeanInstance;
>     }
>     public AppScopedBean() {
>     }
>     public void leakOneInstance() {
>         System.out.println("Leaked!");
>         instanceBeanInstance.get();
>     }
> }

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