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From: markspace <markspace@nospam.nospam>
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Subject: Re: how actually string store in java machine
Date: Tue, 25 Mar 2014 14:00:34 -0700
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On 3/25/2014 1:19 PM, Jeff Higgins wrote:
> On 03/25/2014 04:16 PM, Jeff Higgins wrote:
>> <http://java-performance.info/string-intern-java-7-8-part-3/#more-667>
> Oops.
> <http://java-performance.info/string-intern-java-7-8-part-3>
>
>


Quoted from your link:


"Summary

     "Despite serious optimizations done in the String.intern() 
implementation in Java 7+, it still takes a noticeable time to run 
(noticeable for CPU sensitive applications). The simple example in this 
article runs 3.5 times faster without calls to String.intern(). You 
should not use String.intern() as a safety net, passing every long 
living string into it. Instead process only fields with a limited number 
of possible distinct values (for example, states/provinces if processing 
addresses) - memory savings in this situation will definitely pay off 
the initial CPU costs of String.intern()."

* * *


Basically the "you should not use String.intern() ... passing every ... 
string into it."  Is the money shot.  If you have a string that's 
obviously repetitious (like a field for states or countries) it might be 
useful, other wise not so much.

Also, using String.intern() heavily requires that you increase memory 
available to it.


"The requirement to set -XX:StringTableSize=N JVM parameter in advance 
and dealing with its fixed value"


That alone would make me want to use a HashSet instead.