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Re: A third easy performance optimisation needed

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On Thursday, July 13, 2017 at 7:41:39 AM UTC-4, Eric Sosman wrote:
>      I'm not sure what you intend to say about `final', but I
> hope you're familiar with Brian Goetz' thoughts on the matter:
> 
> https://www.ibm.com/developerworks/java/library/j-jtp04223/index.html#N10087
> 
> https://www.ibm.com/developerworks/java/library/j-jtp1029/index.html

So final classes and methods may not improve performance or definitely won't improve performance?  Even if they do improve performance, if the improvement is insignificant it is a valid point you should not do it unless you definitely don't want the class extended or method overridden.  Oracle does use it occasionally for that reason, notably in the String class.

So final variables don't affect performance either way?  I do use the Eclipse option to automatically declare variables final which are assigned exactly once.  As long as that won't hurt performance it seems a good thing.

These articles were written in 2002-3.  I wonder if it's all still relevant.  I thought the code snippet seemed odd.

// Immutable -- returns an unmodifiable List instead
public class SafeStates {
  private final String[] states = new String[] { "Alabama", "Alaska", ... };
  private final List statesAsList 
    = new AbstractList() {
        public Object get(int n) { 
          return states[n];
        }
 
        public int size() {
          return states.length;
        }
      };
         
  public List getStates() {
    return statesAsList;
  }
}

Why not use Oracle's method?
http://docs.oracle.com/javase/8/docs/api/java/util/Collections.html#unmodifiableList-java.util.List-

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A third easy performance optimisation needed Cecil Westerhof <Cecil@decebal.nl> - 2017-07-13 09:54 +0200
  Re:A third easy performance optimisation needed omegajunior <omegajunior@protonmail.com> - 2017-07-13 06:29 -0400
  Re: A third easy performance optimisation needed Martin Gregorie <martin@address-in-sig.invalid> - 2017-07-13 11:27 +0000
  Re: A third easy performance optimisation needed Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-07-13 07:41 -0400
    Re: A third easy performance optimisation needed Eric Douglas <e.d.programmer@gmail.com> - 2017-07-13 05:48 -0700
      Re: A third easy performance optimisation needed Arne Vajhøj <arne@vajhoej.dk> - 2017-07-13 19:39 -0400
    Re: A third easy performance optimisation needed Cecil Westerhof <Cecil@decebal.nl> - 2017-07-13 15:14 +0200
      Re: A third easy performance optimisation needed Eric Douglas <e.d.programmer@gmail.com> - 2017-07-13 07:07 -0700
        Re: A third easy performance optimisation needed Robert Klemme <shortcutter@googlemail.com> - 2017-07-13 19:58 +0200
          Re: A third easy performance optimisation needed Cecil Westerhof <Cecil@decebal.nl> - 2017-07-13 20:02 +0200
  Re: A third easy performance optimisation needed Arne Vajhøj <arne@vajhoej.dk> - 2017-07-13 08:16 -0400
    Re: A third easy performance optimisation needed Eric Douglas <e.d.programmer@gmail.com> - 2017-07-13 06:08 -0700
      Re: A third easy performance optimisation needed Cecil Westerhof <Cecil@decebal.nl> - 2017-07-13 15:41 +0200
        Re: A third easy performance optimisation needed Eric Douglas <e.d.programmer@gmail.com> - 2017-07-13 07:09 -0700
          Re: A third easy performance optimisation needed Eric Douglas <e.d.programmer@gmail.com> - 2017-07-13 08:07 -0700
          Re: A third easy performance optimisation needed Cecil Westerhof <Cecil@decebal.nl> - 2017-07-13 18:37 +0200
        Re: A third easy performance optimisation needed Joshua Cranmer 🐧 <Pidgeot18@verizon.invalid> - 2017-07-13 13:19 -0500
          Re: A third easy performance optimisation needed Arne Vajhøj <arne@vajhoej.dk> - 2017-07-13 14:32 -0400
      Re: A third easy performance optimisation needed Arne Vajhøj <arne@vajhoej.dk> - 2017-07-13 13:52 -0400
        Re: A third easy performance optimisation needed Eric Douglas <e.d.programmer@gmail.com> - 2017-07-14 07:52 -0700
  A third easy performance optimisation needed lewbloch@gmail.com - 2017-07-14 14:47 -0700

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