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From Jonathan Valliere <jon.valli...@emoten.com>
Subject Re: Java Generics
Date Thu, 11 Oct 2018 17:03:31 GMT
One explaination I came up was that Java is performing a full upcast when
encountering the generic-based interface.  Unchecked and checked genetics
perform identically.

Because the generics are fully removed at compile time; Java may be forced
to do full type casting every time the method is called.

If there isn’t something inherently wrong with the test then there is a big
performance penalty when using generic interfaces.

On Thu, Oct 11, 2018 at 12:50 PM Emmanuel Lécharny <elecharny@gmail.com>
wrote:

> Thanks, Jonathan,
>
> Le 11/10/2018 à 18:07, Jonathan Valliere a écrit :
> > I was having a conversation with a colleague last week about the cost of
> > automatic casting due to the use of generics in java; so, I decided to
> > write a benchmark.  Since everyone wants their networking code to run as
> > fast as possible, I thought I would share it with all of you.
> >
> > Feel free to peer-review the code.
> > https://github.com/jon-valliere/jmh-generics-benchmark
>
> Running this benchmark, I get a 10x slower run when using generic
> compared to the non-generic version (3G op/s vs 300M op/s)
>
> That beaing said, Generic are't supposed to have any impact on java
> code, because it's all removed by the compiler, so there must be
> something weirdo going on. It would be interesting to check the
> generated bytecode to see the difference.
>
>
> --
> Emmanuel Lecharny
>
> Symas.com
> directory.apache.org
>
>

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