RFR: 8315130: java.lang.IllegalAccessError when processing classlist to create CDS archive [v6]

[Timofei Pushkin]

On Thu, 10 Apr 2025 16:04:59 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> Timofei Pushkin has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove findClass, extend explanation comments
>
> test/hotspot/jtreg/runtime/cds/appcds/customLoader/ClassFromClasspath.java line 53:
> 
>> 51:         out.shouldContain("unreg CustomLoadee");
>> 52:     }
>> 53: }
> 
> For completeness, I think we should have a more complicated scenario:
> 
> - load CustomLoadee in both the app loader and a custom loader
> - load CustomLoadeeChild in the custom loader. Its super class should be the one defined in the custom loader
> 
> At run time, verify that CustomLoadeeChild is archived and its super class is defined in the custom loader

This case will work, I've added the test, however I found another case which won't be handled correctly, neither before nor after this change.

This is the case you've suggested, it works fine both before and after the change.

java/lang/Object id: 0
CustomLoadee3 id: 1
CustomLoadee3 id: 2 super: 0 source: a.jar
CustomLoadee3Child id: 3 super: 2 source: a.jar


However the below one doesn't work neither before nor after this change. At dump time, 2 is loaded instead of 1 as the super of 3 because 2, 3 are loaded by the same class loader and 1, 2 have the same name. It is possible to get such class list if 2 is loaded by a non-delegating unregistered loader while 3 is loaded by a different delegating one. 

# Difference with the previous: super of the last class
java/lang/Object id: 0
CustomLoadee3 id: 1
CustomLoadee3 id: 2 super: 0 source: a.jar
CustomLoadee3Child id: 3 super: 1 source: a.jar


And the following case is working without this change but will not work with it. It is working now because there will be two different unregistered loaders for classes 2 and 3 (because they have the same source), however with this change there will be one and it will re-use 2 already loaded by it when loading 3.

# Difference with the previous: source of the last class
java/lang/Object id: 0
CustomLoadee3 id: 1
CustomLoadee3 id: 2 super: 0 source: a.jar
CustomLoadee3Child id: 3 super: 1 source: b.jar

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PR Review Comment: https://git.openjdk.org/jdk/pull/24223#discussion_r2042386067