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https://issues.apache.org/jira/browse/GROOVY-10957?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17695868#comment-17695868
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Nicolas Filotto edited comment on GROOVY-10957 at 3/2/23 7:09 PM:
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According to what I could see from different Profilers' reports (JProfiler,
MAT, and VisualVM), only the primitive classes have a JNI Global Reference as
GC Root. I also called {{InvokerHelper.removeClass(Class)}} on all the classes
loaded by my {{CustomClassLoader}} like what is done in
{{GroovyClassLoader#clearCache()}} but I get the same result.
However, I've just checked and realized that the Integer wrapper class has also
a non-empty {{classValueMap}} so I can try to call
{{InvokerHelper.removeClass(Class)}} on the wrapper classes too to see if it
helps.
was (Author: JIRAUSER285918):
According to what I could see from different Profilers' reports (JProfiler,
MAT, and VisualVM), only the primitive classes have a JNI Global Reference as
GC Root. I also called {{InvokerHelper.removeClass(Class)}} only all the
classes loaded by my {{CustomClassLoader}} like what is done in
{{GroovyClassLoader#clearCache()}} but I get the same result.
However, I've just checked and realized that the Integer wrapper class has also
a non-empty {{classValueMap}} so I can try to call
{{InvokerHelper.removeClass(Class)}} on the wrapper classes too to see if it
helps.
> How to prevent ClassLoader leaks when using ClassValue?
> -------------------------------------------------------
>
> Key: GROOVY-10957
> URL: https://issues.apache.org/jira/browse/GROOVY-10957
> Project: Groovy
> Issue Type: Question
> Affects Versions: 4.0.6
> Reporter: Nicolas Filotto
> Priority: Major
> Attachments: JNI-Global-Reference.png
>
>
> For my tests, I'm using
> [rest-assured|https://github.com/rest-assured/rest-assured] which is
> partially written in Groovy.
> In my application, I use a custom {{ClassLoader}} to load rest-assured and
> Groovy classes, after each test, the {{ClassLoader}} is closed and ready to
> be collected by the GC.
> In case, I launch my tests with {{-Dgroovy.use.classvalue=false}}, the
> {{ClassLoaders}} are properly removed from the heap but when I use
> {{-Dgroovy.use.classvalue=true}}, I end up with an OOME.
> I can see thanks to my profiler that each {{ClassLoader}} is actually
> retained by a JNI Global Reference to each primitive class ({{void.class}},
> {{float.class}}, {{boolean.class}}, {{int.class}}, {{double.class}},
> {{long.class}}, {{char.class}}, {{byte.class}}).
> If I naively call {{InvokerHelper.removeClass(Class)}} on each of these
> classes, my {{ClassLoaders}} don't have any GC root anymore but
> unfortunately, they are still in the heap.
> I created a small project to reproduce
> https://github.com/essobedo/testCLLeak, any idea/help is more than welcome.
> *_Environment:_*
> +Java version:+
> {noformat}
> openjdk version "11.0.18" 2023-01-17
> OpenJDK Runtime Environment Temurin-11.0.18+10 (build 11.0.18+10)
> OpenJDK 64-Bit Server VM Temurin-11.0.18+10 (build 11.0.18+10, mixed mode)
> {noformat}
> +OS:+
> {noformat}
> Darwin LT-C02CP37VMD6R 22.3.0 Darwin Kernel Version 22.3.0: Mon Jan 30
> 20:42:11 PST 2023; root:xnu-8792.81.3~2/RELEASE_X86_64 x86_64
> {noformat}
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