RFR: 8313816: Accessing jmethodID might lead to spurious crashes

[David Holmes]

On Mon, 20 Nov 2023 21:48:11 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> The method holder is an `InstanceKlass` object which can be retrieved as `method->method_holder()` (I apologize if I am using not completely correct terms - this is what I grokked from the sources). And incomplete methods created by the `ClassParser` from the class data stream will not have the link to that `InstanceKlass` set up if the `ClassParser` is already having its `_klass` field set to a non-null value.
>> 
>> If we are talking about clearing any jmetbodIDs associated with an `InstanceKlass` instance it is not really possible for old method versions because only the current `InstanceKlass` version has the jmethodID cache associated with it and it contains jmethodIDs pointing to bot the old and current methods.
>
> I see, holder is the right word and concept.  So the parameter means has_method_holder, in that the InstanceKlass has been fully parsed at the point of clearing the jmethodIDs.

Can't we just check `method->method_holder()` for null rather than passing in a parameter like this?

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PR Review Comment: https://git.openjdk.org/jdk/pull/16662#discussion_r1401396222