Need reviewer for forward port of 6815768 (File.getXXXSpace) and 6815768 (String.hashCode)

[Ulf Zibis]

Am 25.02.2010 23:07, schrieb Alan Bateman:
> Kelly O'Hair wrote:
>> Yup.  My eyes must be tired, I didn't see that. :^(
> Too many repositories in the air at the same time. The webrev has been 
> refreshed. Thanks Ulf.
>
>

Another thought:

In the constructors of String we could initialize hash = 
Integer.MIN_VALUE except if length == 0.
Then we could stay at the fastest version:

     public int hashCode() {
         int h = hash;
         if (h == Integer.MIN_VALUE) {
             h = 0;
             char[] val = value;
             for (int i = offset, limit = count + i; i != limit; )
                 h = 31 * h + val[i++];
             hash = h;
         }
         return h;
     }

As an alternative we could use:
private static final int UNKNOWN_HASH = 1;
Justification:
Using a small value results in little shorter byte code and machine code 
footprint after compilation.
Additionally on some CPU's this likely will perform little better, but 
never worse.

Please note:
Original loop causes 2 values to increment:
             for (int i = 0; i < len; i++) {
                 h = 31*h + val[off++];
             }
This is inefficient as I have proved in a little micro-benchmark.

-Ulf