RFR: 8220607 Draft JEP: Hidden Classes
brian.goetz at oracle.com
Fri Dec 6 22:51:50 UTC 2019
> Another asymmetry between Lookup::defineClass and defineHiddenClass is
> the return value, Class vs Lookup.
> It's trivial to get the class from a Lookup object but we can't go the
> other way. If a framework wants to get Lookup from a hidden class it
> just defines (e.g. get a MethodHandle and invoke), if dHC returned a
> Class, the hidden class had to provide an entry point to return its
> Lookup object. Such entry point has to be accessible to the framework
> but it has to be cautious in leaking its full-power Lookup.
For the reasons you give, this asymmetry doesn't bother me. Most users
of dC will want the class; users of dHC will generally _need_ the lookup.
> I have considered adding Lookup::defineClassAsLookup(byte bytes,
> boolean initialize). Lookup::defineClass was added in JDK 9. I
> haven't seen any request to initialize the class. So I think it can
> be done as a separate enhancement. I will file a JBS issue.
I agree that this should be a separate enhancement. I'd like to see this
bit of unsafe removed too, but no need to hold up this train to get to
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