RFR: 8264707: HotSpot Style Guide should permit use of lambda

[Kim Barrett]

> On Sep 9, 2021, at 8:10 AM, Andrew Haley <aph-open at littlepinkcloud.com> wrote:
> 
> On 9/9/21 12:25 AM, Kim Barrett wrote:
>> Because of restrictions we're imposing on lambda usage, and in particular
>> requiring only downward usage, it should be possible to create such a holder
>> that isn't too complicated either to implement or to use, and also avoids
>> memory allocation.
> 
> OK, but for now I guess we can use Lambdas in some simple case that make
> HotSpot clearer and easier to write.

I also think we don't need to solve the type-erased capture problem before
we start using lambdas.  It would be good to get opinions from others.

And just in general, this PR hasn't generated much discussion or approvals.
I expected more of one or both.  We're well past the originally suggested
decision date, but I don't feel comfortable calling this done.  Maybe folks
just forgot about it and this will serve as a reminder.