RFR: 8172905: Minor startup cleanup of CallSite and MethodType

[Paul Sandoz]

> On 17 Jan 2017, at 08:06, Claes Redestad <claes.redestad at oracle.com> wrote:
> 
> Hi,
> 
> as a follow-up to JDK-8086045, further analysis has found a number of small, simple improvements that can be made to further improve startup characteristics of typical usage of java.lang.invoke:
> 
> - CallSite::<clinit> looks up two MethodHandles that aren't used in many typical applications and should be lazily constructed
> - CallSite.CONTEXT_OFFSET is calculated but never used
> - The ConcurrentHashMap in MethodType$ConcurrentWeakInternSet is resized multiple times even for relatively trivial tests, and initializing it to a larger size is footprint neutral but beneficial to startup to many applications
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8172905
> Webrev: http://cr.openjdk.java.net/~redestad/8172905/webrev.01/
> 
> This small set of relatively non-intrusive changes has a measurable impact to startup - generates fewer classes on some tests, does less work on all - which partially help with a number of startup regressions tracked in 9 due to heavier and earlier use of j.l.invoke.
> 

Look ok.

It’s either place the static finals in separate nested classes, or use @Stable on non-final statics with lazy initialization in methods (with the possibility of multiple invocations when concurrently executing). Nested classes seems fine here.

Paul.