RFR: 8284336: CDS SignedJar.java test fails due to archived Reference object

[Ioi Lam]

On Fri, 8 Apr 2022 07:08:29 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> During `java -Xshare:dump`, `ClassLoaders.bootLoader().resourceCache` is usually null. However, if a signed class is loaded, `resourceCache` will point to a `java.lang.ref.SoftReference`. Although rare (we have never seen this during our testing), it's possible for `resourceCache.discovered` to directly or indirectly point to another `Reference` which may contain an object that cannot be archived.
>> 
>> The fix is simple: reset the `resourceCache` field of all three archived ClassLoader objects (boot/platform/app).
>> 
>> I cannot reproduce the problem and I am unable to write a deterministic test case. However, the bug reporter has tested my preliminary patch and is no longer able to reproduce the failure.
>> 
>> Please see the bug report [JDK-8284336](https://bugs.openjdk.java.net/browse/JDK-8284336) for detailed analysis and traces.
>
> The updates to resetArchivedStates look okay.

Thanks @AlanBateman and @calvinccheung for the review!

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PR: https://git.openjdk.java.net/jdk/pull/8151