RFR: 8332105: Exploded JDK does not include CDS

[Ioi Lam]

On Mon, 27 May 2024 09:13:25 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> > > Seems okay. This test should have had `requires vm.cds` anyway.
> > > Just out of curiosity why is CDS not compatible with an exploded build?
> 
> @dholmes-ora Thanks for the review. Honestly, I don't know. Maybe @iklam knows.
> 
> > Isn't the exploded build supposed to be as fast as possible? I think that's why people use it, and it'd be a shame to allow anything, such as building a CDS arcive, to slow that process down.
> 
> Sure, but not generating a CDS archive at build time and being unable to dump or use an archive at all are two different things.

The exploded build has tens of thousands of class files. If any of them are modified, the CDS archive may no longer be valid. There's no quick way of checking that. That's why CDS doesn't support the exploded build (or any apps that load class files from a directory).

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PR Comment: https://git.openjdk.org/jdk/pull/19188#issuecomment-2134378616