RFR: JDK-8282776: Bad NullPointerException message when invoking an interface MethodHandle on a null receiver [v2]

[Mandy Chung]

On Fri, 11 Mar 2022 22:49:25 GMT, Mandy Chung <mchung at openjdk.org> wrote:

>> A simple patch to call `Objects.requireNonNull(recv)` for an explicit null receiver check rather than NPE thrown by `Object::getClass`.  The message of NPE generated by JEP 358 (Helpful NullPointerExceptions) is supposed to be helpful but not in this case.
>
> Mandy Chung has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - Move the null check after isInstance check
>  - Merge branch 'master' of https://github.com/openjdk/jdk into JDK-8282776
>  - JDK-8282776: Bad NullPointerException message when invoking an interface MethodHandle on a null receiver

I did a quick sanity run of the reflection microbenchmarks.  I eyeball the numbers and don't spot any difference.

OTOH, since the `isInstance` check covers the null check, moving the null check inside the exception case is a better fix.

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PR: https://git.openjdk.java.net/jdk/pull/7766