Any::isNull check

[Brian Goetz]

> I really dislike this percentile breakdown that you've mentioned 
> several times on this list.  JDK core libs developers themselves have 
> to deal with this, and that code is used by many people with some 
> expectation of performance.  The whole value type project is 
> performance geared! 

Yes.  JDK developers have to, and are willing to, code in ways we're not 
willing to ask other people to code.  We're fully aware of the need to 
make these things *possible*.  But we're also quite aware of what it is, 
and isn't, reasonable to ask of developers in terms of how regular 
developers write their code.  And we are for sure not going to let 
micro-performance issues like this drive how the majority of users are 
expected to code.

> Moreover, nobody is suggesting some sharp tool be added only for 
> experts.  I'm simply saying that given the choice of presenting more 
> byte code vs less makes a difference.  If there's a reasonable way to 
> present less it's a win.  Saying JIT is really good at eliminating 
> dead code is, while true, not the full picture when the topic is 
> performance.

Performance is not the full picture either.

Quite honestly, at this point, micro-performance issues like this should 
not even be part of the discussion at all.  We are well aware of the 
performance tradeoffs that await us in the event we actually get to a 
model that we think is good enough to foist on Java users. But its 
simply way too early to deep-dive on micro-performance issues like this 
-- while this will eventually be important, at this early stage, its a 
distraction.

So, can we please go back to work now?