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

[Claes Redestad]

On Wed, 9 Mar 2022 22:52:41 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.

Historically I've found that `Objects.requireNonNull` compile down to be roughly equivalent to an implicit null check as long as a NPE is actually never thrown, see https://bugs.openjdk.java.net/browse/JDK-8042127 

With the recent change to force-inline `requireNonNull` the profile pollution part of this issue might no longer be relevant. I'll see if I can carve out time to do some experiments to revisit and perhaps even close out that old bug, but I don't think this is much to worry about for this change since provoking such NPEs should be rare in production settings. Always a risk adding explicit calls, of course: A few added cycles on startup, a few extra bytecode that _could_ interfere with inlining of the `checkReceiver` method.. 

I suggest a quick sanity run of our reflection (micro)benchmarks

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