This change seems good all around. In addition to fixing the noted race, it removes a substantial amount of redundant instance footprint from a class whose instances are not infrequently collected in significant numbers-- fields most of which just served methods that are essentially never used in critical code anyway. Of course hashCode is used, but it's not computationally like String.hashCode.
Agree with Alan that the code for variant() requires an extra stare to make sense of, so more comment might be helpful-- otherwise looks good to me. -- Peter On Tue, Feb 22, 2011 at 7:29 PM, Mike Duigou <mike.dui...@oracle.com> wrote: > Daniel Aioanei reported via Josh Bloch a data race issue with the UUID > accessor and hashCode() methods. I've prepared a webrev with the suggested > changes: > > http://cr.openjdk.java.net/~mduigou/6611830/webrev.0/webrev/ > > I've tested the change against the standard UUID tests and did a > microbenchmark test of one method, variant(), to see what impact not caching > had on performance. Since there was only negligible change in performance vs. > the existing UUID implementation I am comfortable with eliminating the cache > values. It would appear that a field access plus a shift is not a significant > cost over a field access. > > Mike
