Spec updates for method parameter reflection

[Alex Buckley]

On 11/10/2012 4:40 AM, Remi Forax wrote:
> I think the default policy (don't include parameter names) is not the
> good one. While I agree that enable reified parameter everywhere can
> severely impact class file size (the runtime part can be lazy), there
> is a third option between enable and disable, enable parameter names
> selectively.
>
> I propose the following default policy, parameter names are enabled
> by default only if the methods is annotated with an annotation with
> the retention CLASS or RUNTIME.
>
> The idea is that if the method is annotated, the parameter names
> should be visible by a class enhancer or the reflection API.

There are many ideas for an "opt in" mechanism:

- Explicit: @ReifyParameters annotation on a class
- Explicit: @ReifyParameters annotation on a method
- Semi-explicit: @ReifyParameters meta-annotation on a class annotation
- Semi-explicit: @ReifyParameters meta-annotation on a method annotation
- Implicit: Presence of any RUNTIME-retention annotation on a class
- Implicit: Presence of any RUNTIME-retention annotation on a method
- Implicit: Presence of any CLASS/RUNTIME-retention annotation on a class
- Implicit: Presence of any CLASS/RUNTIME-retention annotation on a method

Opinions differ on which is best. It seems risky at this time to commit 
to one mechanism, since it would have to be supported forever even if 
consensus comes round to a different mechanism. For this reason, we will 
avoid defining a standard "opt in" mechanism for Java SE 8.

Alex