Be able to invoke a MethodHandle directly

[Rémi Forax]

Hi John,
During the JVM Summit, you say that BGGA closure is the major use case
for allowing to call a MethodHandle directly using its method "invoke".
I don't think it's a good example since BGGA closures are 
covariant/contravariant,
so the MethodHandle behind a closure can't be called directly because it 
need to be adapted.

So I don't see a 'real' use case for calling a MethodHandle directly.

For the backport, emulate this call is a performance problem because
unlike invokedynamic that requires to use Linkage.registerBootstrapMethod()
on classes that contains at least one invokedynamic call site
there is no such requirement for MethodHandle.invoke()
a MethodHandle.invoke can be done anywhere
so I have to inspect all loaded classes.

I know that invokedynamic spec should not be changed because
it will improve the backport speed, but is there a use case for that 
feature ?


Rémi