RFR: 8371953: Document null handling in core reflection APIs [v2]

[Chen Liang]

On Sun, 16 Nov 2025 17:11:35 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> Chen Liang has updated the pull request incrementally with three additional commits since the last revision:
>> 
>>  - Rephrase for parameterTypes contains null
>>  - Rename tests to be more specific
>>  - Split annotated type new checks to another patch
>
> src/java.base/share/classes/java/lang/Class.java line 2152:
> 
>> 2150:      *         {@code name} and {@code parameterTypes}
>> 2151:      * @throws NoSuchMethodException if a matching method is not found, such as
>> 2152:      *         when {@code parameterTypes} contains {@code null},
> 
> It might be clearer to say "or parameterTypes contains a null element" rather than "such as when ..."

My impression of this behavior is that no method can have a parameter type array that contains a `null` value. So claiming there is no matching method for this scenario probably makes sense?

> Now we have this odd scenario where a null element will provoke an eager NPE if flag is true

Sorry, but I fail to see where that happens - I believe if the array has a null element, `array.clone()` executes successfully, and the NPE is only thrown after some elements are set accessible. If the array is null, the array iteration would immediately fail with a NullPointerException just like when clone is executed. So both `false` and `true` paths would have the same NPE behavior.

In addition, the other exceptions of this methods are already thrown with side effects on the elements in the array before the first null value, and the side effects is not additionally specified. I think we can specify the NPE without requiring the NPE to be thrown before any side effect has been committed.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28336#discussion_r2532159152
PR Review Comment: https://git.openjdk.org/jdk/pull/28336#discussion_r2532158581