java.util.UUID.fromString performance

Mike Duigou mike.duigou at
Tue Feb 28 17:37:01 UTC 2012

The easiest wat to proceed would be for you to submit a webrev patch with both changes along with your microbenchmark test. Once the change is incorporated in the jdk8 mainline the sustaining teams can evaluate it for backporting to jdk 7 and 6.


On Feb 28 2012, at 06:26 , Vitaly Davidovich wrote:

> Hi all,
> I noticed that this method could be made a bit more performant by:
> 1) creating a statically initialized Pattern for "-" and then calling
> split() on that.  Currently the method calls name.split() which compiles
> the pattern on each invocation.
> 2) use Long.parseLong() instead of Long.decode() to extract the bits.
> With these changes, the method runs at least 20% faster (some runs were
> significantly faster) on an Intel Westmere server and should be a bit more
> GC friendly.
> Any thoughts? I can send the full code a bit later when I'm in front of my
> computer.
> Thanks
> Sent from my phone

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