On Fri, 1 Aug 2025 20:19:33 GMT, Chen Liang <li...@openjdk.org> wrote:
>> src/java.base/share/classes/jdk/internal/misc/Unsafe.java line 1093:
>>
>>> 1091: * startup. This should not be used to find fields in
>>> non-trusted code.
>>> 1092: * Use the {@link #objectFieldOffset(Field) Field}-accepting
>>> version for
>>> 1093: * arbitrary fields instead.
>>
>> It’s also used to obtain offsets of fields in classes which have their
>> fields filtered from reflection using
>> `Reflection::registerFieldsToFilter(…)`, such as fields in
>> `java.lang.ClassLoader` or `java.lang.Module`.
>
> I don't think this is ever the intention of
> [JDK-8182487](https://bugs.openjdk.org/browse/JDK-8182487)
> (928ca49c21d7e571e88dd27cf47033bf88d2dc71) - it is a side effect, and you can
> always query the VM for a Field object if you are determined, or
> java.lang.invoke.MemberName can be used to obtain an offset for filtered
> fields too.
In an analogy, you could argue the existing `objectFieldOffset` can be used to
obtain offsets of static fields in classes. Clearly that is a wrong way to use
it; for internal APIs, we have the freedom to explicitly stop supporting some
usages we deem deviating from our purpose, unlike the compatibility
requirements imposed on public APIs like sun.misc.Unsafe.
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PR Review Comment: https://git.openjdk.org/jdk/pull/25945#discussion_r2248808092
