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From Chris Lambrou <>
Subject Re: [collections] Porting to JDK 1.5 and Generics
Date Wed, 02 Mar 2005 16:55:30 GMT
Hi Lukas,

Whilst generic collections provide type safety at compile time, at 
runtime all of the specific type information is erased and the 
collections classes behave much the same way as their Java 1.4 
predecessors.  With respect to the actual implementations of the classes 
within the Java Collections Framework, having spent a fair amount of 
time looking at them, I see nothing to suggest that their 
reimplementation in Java 5  would give rise to any performance 
improvement. The only noticeable change to the collections classes is 
their generification.  Any specific performance improvements that you 
may observe are likely to be due to more general performance 
improvements that have been made to Sun's Java 5 JRE (note that it's 
possible that some of these improvements may also have been included in 
the recent latest releases of the 1.4 JDK).


Lukas Vlcek wrote:

>Is there any performance gain in <Generics> Collections in Java5? Can
>I expect performace improvement or specialized type collection
>libraries (like fastutil) will be always faster.

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