jdk22 WrapperHiddenClassTest: MHP impl class cannot be cleared by GC

[babsingh]

https://openj9-jenkins.osuosl.org/job/Test_openjdk22_j9_sanity.openjdk_aarch64_linux_Personal_testList_0/1
jdk_lang
java/lang/invoke/MethodHandleProxies/WrapperHiddenClassTest.java

16:34:54  STARTED    WrapperHiddenClassTest::testWeakImplClass '[2] interface Client'
16:34:54  org.opentest4j.AssertionFailedError: MHP impl class cannot be cleared by GC
16:34:54  	at [email protected]/org.junit.jupiter.api.AssertionUtils.fail(AssertionUtils.java:38)
16:34:54  	at [email protected]/org.junit.jupiter.api.Assertions.fail(Assertions.java:135)
16:34:54  	at WrapperHiddenClassTest.testWeakImplClass(WrapperHiddenClassTest.java:209)
... 
16:34:54  FAILED     WrapperHiddenClassTest::testWeakImplClass '[2] interface Client'

[babsingh]

There are two WrapperHiddenClassTest failures: this issue and #18805. The failures only happen with gencon and optthruput GC policies. WrapperHiddenClassTest consistently passes with metronome and balanced GC policies.

fyi @dmitripivkine

[dmitripivkine]

There are two WrapperHiddenClassTest failures: this issue and #18805. The failures only happen with gencon and optthruput GC policies. WrapperHiddenClassTest consistently passes with metronome and balanced GC policies.

fyi @dmitripivkine

Such set of GC policies points to the JIT most likely. There are many JIT optimizations disabled for Metronome and Balanced. Another possibility for such set that Discontiguous array can be involved, code might expect contiguous array mistakenly.

[dmitripivkine]

@babsingh Would you please help to triage this?
I need:

• link to the test source
• help to generate system core to look at
• nice to have comments what test trying to achieve and what is failed (ideally with references in the core)

[babsingh]

link to the test source

16:34:54 at WrapperHiddenClassTest.testWeakImplClass(WrapperHiddenClassTest.java:209)

https://github.com/ibmruntimes/openj9-openjdk-jdk22/blob/1159998e1cb3beb441d35bc1ca6aea768d6c9afb/test/jdk/java/lang/invoke/MethodHandleProxies/WrapperHiddenClassTest.java#L209

nice to have comments what test trying to achieve and what is failed (ideally with references in the core)

Tests the caching and weak reference of implementation classes for system and user interfaces. Test expects the GC to clear the weak reference after the strong reference has been cleared.

help to generate system core to look at

This failure is intermittent, and the failure in #18805 is dominating the test runs. I will share a link to the core file once I generate it.

[pshipton]

This can be closed now that #19020 is merged?

[babsingh]

I had locally verified that #19020 fixes this issue. I have opened adoptium/aqa-tests#5116 to re-enable the test.