On Mon, 15 Dec 2025 16:04:10 GMT, Chen Liang <[email protected]> wrote:
>> The 3 methods to determine conversions and subtyping on `java.lang.Class`,
>> which are `isInstance`, `cast`, and `isAssignableFrom`, have their
>> documentation from the earliest days of the Java Platform. During the
>> language evolution, a lot of terms have become inaccurate, such as
>> "assignment-compatible", which does not apply for primitive types, and the
>> out-of-date instanceof analogy with the upcoming patterns, in `isInstance`;
>> `isAssignableFrom` is not very clear about arrays; `cast` would also benefit
>> from more detailed explanations.
>>
>> In my facelift, I moved the subtyping description to `isAssignableFrom`, and
>> left the conversion stuff in `isInstance` and `cast`. I intentionally
>> avoided linking to too many JLS chapters to reduce confusions. I believe in
>> this shape, we have a good amount of easily comprehensible yet accurate
>> specification for all 3 methods, and users are welcome to read the linked
>> JLS chapters for more details and context.
>
> Chen Liang has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Stage
src/java.base/share/classes/java/lang/Class.java line 758:
> 756: * @param obj the reference to check, an object or {@code null}
> 757: * @return true the reference type represented by this {@code Class}
> is
> 758: * a supertype of the class of {@code obj}; false otherwise
Missing “if”:
Suggestion:
* @return true if the reference type represented by this {@code Class}
* is a supertype of the class of {@code obj}; false otherwise
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PR Review Comment: https://git.openjdk.org/jdk/pull/28684#discussion_r2637236468
