On Sat, 15 Nov 2025 23:04:53 GMT, Chen Liang <[email protected]> wrote:
> A lot of core reflection APIs are from antique times, which have their own
> null handling behavior. Such behaviors are often not documented in the
> specification; we should document rejected null arguments and accepted null
> arguments (including array elements) explicitly.
>
> In the investigation, I found `Class.isNestmateOf` (inconsistent) and
> `AnnotatedType`'s implementation of `AnnotatedElement` methods (required by
> specification) are missing null checks. I consider these unlikely to be a
> user dependency and added new null checks.
src/java.base/share/classes/java/lang/Class.java line 2148:
> 2146: *
> 2147: * @param name the name of the method
> 2148: * @param parameterTypes the list of parameters, may be or contain
> {@code null}
The method description already specifies that if parameterTypes is null then it
works like an empty array, so "may be null" is okay here.
getMethod, getConstructor, ... throw NoSuchMethodException is the
parameterTypes has a null element. Maybe it would be better to expand the
description for `@throws NoSuchMethodException`? That would avoid suggesting in
the parameter description that a null element is allowed.
src/java.base/share/classes/java/lang/Class.java line 3839:
> 3837: */
> 3838: public boolean isNestmateOf(Class<?> c) {
> 3839: Objects.requireNonNull(c);
So the behavior change here is calling isNestmateOf(null) on a class object for
a primitive or array class will throw NPE when it didn't throw it previously.
Technically an incompatible change but I agree it's in the weeds when it comes
to impact.
test/jdk/java/lang/Class/APIContractTest.java line 35:
> 33: import static org.junit.jupiter.api.Assertions.*;
> 34:
> 35: class APIContractTest {
We have a lot of existing tests that exercise the "API contract" so I think the
naming of most of the tests is in this PR is a bit misleading - maybe start out
with NullTests or something that makes it clear from the names that these are
tests that fire nulls at everything. If some of these tests expand purpose in
the future then they can be renamed.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/28336#discussion_r2531754070
PR Review Comment: https://git.openjdk.org/jdk/pull/28336#discussion_r2531755438
PR Review Comment: https://git.openjdk.org/jdk/pull/28336#discussion_r2531707408
