RFR 8062180: MethodHandleImpl.makeArrays throws and swallows java.lang.NoSuchFieldError in normal flow

[Claes Redestad]

Hi,

please review this minor improvement to the initialization of 
MethodHandleImpl$Lazy. Running any code which initializes 
MethodHandlesImpl$Lazy will trigger throwing of 
java.lang.NoSuchFieldErrors, which has a measurable impact on startup.

Additionally, the current lookup via findCollector in varargsArray is 
pointless (and will throw additional java.lang.NoSuchFieldErrors the 
first time a varargsArray of arity > 11 is requested) since all static 
methods which can be found will have been constructed already.

bug: https://bugs.openjdk.java.net/browse/JDK-8062180
webrev: http://cr.openjdk.java.net/~redestad/8062180/webrev.00/

A simple microbenchmark[1] show a very small (~0.5ms) improvement for 
Class.forName("java.lang.invoke.MethodHandleImpl$Lazy")

Benchmark                               Mode  Samples   Score Score 
error  Units
o.s.CLBench.loadMethodHandleImplLazy ss      100  46.364        
1.740     ms
o.s.CLBench.loadMethodHandleImplLazy      ss      100 45.440        
1.515     ms

Thanks!

/Claes

[1] package org.sample;

import org.openjdk.jmh.annotations.*;
import javax.script.*;

@State(Scope.Thread)
public class CLBench {

     @Benchmark
     public Object loadMethodHandleImplLazy() throws Exception {
         return Class.forName("java.lang.invoke.MethodHandleImpl$Lazy");
     }
}