On Mon, 30 Nov 2020 20:57:32 GMT, Harold Seigel <[email protected]> wrote:
>> src/java.base/share/classes/java/lang/Class.java line 4480:
>>
>>> 4478: }
>>> 4479:
>>> 4480: private native Class<?>[] getPermittedSubclasses0();
>>
>> Does this JVM method return the permitted subclasses or subinterfaces with
>> the following conditions enforced by JLS:
>>
>> - If a sealed class C belongs to a named module, then every class named
>> in the permits clause of the declaration of C must belong to the same module
>> as C
>> - If a sealed class C belongs to an unnamed module, then every class
>> named in the permits clause of the declaration of C must belong to the same
>> package as C
>>
>> I didn't check the VM implementation.
>>
>> If the return array contains only classes as specified above,
>> `checkPackageAccessForClasses` can be simplified.
>
> The JVM method that returns the permitted subclasses (and interfaces) does
> not weed out permitted subclasses based on the above module requirements. It
> returns all the classes listed in the PermittedSubclasses attribute that it
> is able to load.
So it could also return a class listed in `PermittedSubclasses` attribute but
not a subclass of this sealed class, right?
The specification of `Class::getPermittedSubclasses` says:
> Returns an array containing {@code Class} objects representing the direct
> subclasses or direct implementation classes permitted to extend or direct
> subinterfaces or subclasses permitted to extend or implement this class or
> interface if it is sealed.
I expect that `Class::getPermittedSubclasses` should do more work and return
only the subclasses or subinterfaces permitted at runtime.
-------------
PR: https://git.openjdk.java.net/jdk/pull/1483
