java.util.UUID.fromString performance

Vitaly Davidovich vitalyd at
Tue Feb 28 14:26:35 UTC 2012

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


Sent from my phone

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