String interning

Tyler Baker tyler at infinet.com
Mon Jan 17 22:43:45 GMT 2000


Miles Sabin wrote:

> David Megginson wrote,
> > For comparison, I just whipped up a Java class to compare two
> > (non-equal) Strings 10,000,000 times.  Here are the USER
> > timings:
> >
> > No comparisons (startup overhead): 0.67 seconds
> > Compare with ==:                   0.94 seconds (=0.2 seconds)
> > Compare with equals():             8.00 seconds (=7.33 seconds)
> >
> > That's a very significant performance difference.
>
> It's also a completely meaningless one unless we can see the
> code and know something about the platform you're running on.
> I'd be quite surprised if there was that much margin with a
> Sun 1.2 JDK and Hotspot on Solaris or Win32.

You will get similiar results on every platform you test it on unless the JVM authors
figure out a way to make testing for object identity more expensive than dynamic method
invocation. Doing that would take some real talent (-:

Regards,

Tyler


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