It seems to me that if two threads call this Math.random() at the same
time then two instances of Random() can be constructed. That contradicts
the specification of the method, and is theoretically observable because
the two values from Math.random() will typically not be a pair of values
that could have been returned from consecutive calls to nextDouble() on
a single Random instance. Granted, the chances of this actually
mattering are infinitesimal, but I think the performance gain of
avoiding a synchronized method only on the very first call to
Math.random() is infinitesimal too. So I'd be inclined to leave well
enough alone here.
Eamonn
Martin Buchholz wrote:
Here's an optimization for Math.random() that appears to be safe,
despite the double-check access:
http://cr.openjdk.java.net/~martin/webrevs/openjdk7/Math.random/
David, if you agree, could you file a bug?
Thanks,
Martin
