RFR: 8375654: Exclude all array classes from dynamic CDS archive

Vladimir Kozlov kvn at openjdk.org
Thu Jan 22 17:44:37 UTC 2026


On Thu, 22 Jan 2026 02:49:17 GMT, Ioi Lam <iklam at openjdk.org> wrote:

> In `A` is a subtype of `B`,  it's possible for an `ObjArrayKlass` for `A[]` to be archived in the dynamic CDS archive and its `_secondary_supers` contains a pointer to an `ObjArrayKlass` for `B[]` that's also archived in the dynamic archive. 
> 
> This scenario used to be supported, but since [JDK-8374639](https://bugs.openjdk.org/browse/JDK-8374639), if `B` is archived in the static CDS archive, at runtime a different `B[]` is created dynamically. As a result, we can no longer typecast an instance of `A[]` into an instance of `B[]`.
> 
> Since `ObjArrayKlasses` are cheap to allocate at runtime, the easiest fix is to simply not store any  `ObjArrayKlass` in the dynamic CDS archive.
> 
> (I also added missing copyright header to a problem list file used by CDS/AOT testing).

Good.

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Marked as reviewed by kvn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/29356#pullrequestreview-3693740553


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