RFR: 8315130: java.lang.IllegalAccessError when processing classlist to create CDS archive [v12]

[Ioi Lam]

On Wed, 14 May 2025 08:18:39 GMT, Timofei Pushkin <tpushkin at openjdk.org> wrote:

>> If a base class is package-private then its subclasses should have the same package name and defining class loader, otherwise `IllegalAccessError` is thrown when linking a subclass. Currently when dumping a static archive separate `URLClassLoader`s are used for each unregistered classes' source. Thus if two unregistered classes, a package-private base class and a sub class, from the same package reside in different sources `IllegalAccessError` will be thrown when linking the sub class. This can be unexpected because the app could have used a single class loader for both classes and thus not have seen the error — see `DifferentSourcesApp.java` from this patch for an example of such app.
>> 
>> This patch fixes the issue by using a single class loader for all unregistered classes. CDS does not allow classes with the same name making such solution possible.
>
> Timofei Pushkin has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Make supertype obstruction check easier to understand

I have merged your PR with the latest repo and running tiers 1-4 in our CI. Waiting for the results now.

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PR Comment: https://git.openjdk.org/jdk/pull/24223#issuecomment-2885610681