RFR: JDK-8282776: Bad NullPointerException message when invoking an interface MethodHandle on a null receiver [v3]

[ExE Boss]

On Tue, 22 Mar 2022 17:55:13 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 incrementally with one additional commit since the last revision:
> 
>   Add exception message

This needs to use `String.format(…)` in order to avoid circular dependencies in bootstraps on `java.lang.invoke.StringConcatFactory`.

src/java.base/share/classes/java/lang/invoke/DirectMethodHandle.java line 424:

> 422:                     throw new IncompatibleClassChangeError(msg);
> 423:                 } else {
> 424:                     throw new NullPointerException("Cannot invoke " + member + " with null receiver");

Suggestion:

                    String msg = String.format("Cannot invoke %s with null receiver",
                                               member);
                    throw new NullPointerException(msg);

src/java.base/share/classes/java/lang/invoke/DirectMethodHandle.java line 456:

> 454:                     throw new IncompatibleClassChangeError(msg);
> 455:                 } else {
> 456:                     throw new NullPointerException("Cannot invoke " + member + " with null receiver");

Suggestion:

                    String msg = String.format("Cannot invoke %s with null receiver",
                                               member);
                    throw new NullPointerException(msg);

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