RFR: JDK-8272192 Shortcut String equality checks by checking equality of the value array [v2]

[David Holmes]

On Mon, 6 Sep 2021 06:45:07 GMT, q2q-2q2 <github.com+44376158+q2q-2q2 at openjdk.org> wrote:

>> Shortcut String equality checks by checking equality of the value array
>
> q2q-2q2 has updated the pull request incrementally with one additional commit since the last revision:
> 
>   JDK-8272192 Shortcut String equality checks by checking equality of the value array

It isn't obvious to me that this is necessarily correct - do we only ever share the full array? IIRC at one time substrings also shared the same array but with different a starting index and length.

If this is correct then it needs some supporting performance data, but as these methods are also VM intrinsics I doubt you will see much difference as only interpreted code will be affected by your change. But I'll leave it to the performance experts to comment - paging @cl4es :)

Oh and as the JBS issue is filed against hotspot as the moment that needs to be cleaned up to, if this is just a Java fix.

Cheers,
David

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PR: https://git.openjdk.java.net/jdk/pull/5370