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From "Juozas Baliuka" <bali...@mwm.lt>
Subject Re: [primitives] Open for business
Date Tue, 02 Sep 2003 11:03:08 GMT

----- Original Message -----
From: "Hope, Matthew" <Matthew.Hope@capitalone.com>
To: "'Jakarta Commons Developers List'" <commons-dev@jakarta.apache.org>
Sent: Tuesday, September 02, 2003 10:26 AM
Subject: RE: [primitives] Open for business


> perhaps less so from 1.5 onwards since for non critical performance the
ease
> of autoboxing is hard to beat but when you are using primitives not just
> because of other interface concerns but for performance/space
considerations
> a pure primitive implementation should be considerably better for large
> sizes. An array of int[1000000] for example takes up 4 bytes per entry*
> verses an Object array of Integers which takes 20 bytes per entry on
> average.
>
> This is 5 times the space! When you use short[] vs Short the difference is
a
> factor of 10

All of boolean, byte, short, int, object reference and float use the same
space in JVM (4 bytes) double and long are 8 bytes.
And all of primityve wrappers have  single primityve field, objects can use
some internal JVM data structures, but I do not think factor can be 10, how
do you tested it ?

>
> given that the underlying implementation of IntArrayList will almost
> certainly be an array of ints this makes a lot of sense if you care about
> the size of your memory footprint...
>
> Matt
>
> * all done on windows 1.3.1 JVM - some jvms may do things differently YMMV
>
> > -----Original Message-----
> > From: Yoav Shapira [mailto:yoavs@apache.org]
> > Sent: 02 September 2003 03:49
> > To: Jakarta Commons Developers List
> > Subject: Re: [primitives] Open for business
> >
> >
> > Howdy,
> > I may have missed the original discussion, but is primitives
> > going to have
> > much of a market given the relative proximity of JDK 1.5 with its
> > autoboxing features?  Or are there a bunch of features
> > planned that aren't
> > going to be in JDK 1.5 anyways?
> >
> > Yoav Shapira
> >
> > On Tue, 2 Sep 2003, Stephen Colebourne wrote:
> >
> > > The [primitives] project has been created and is now ready
> > for discussion,
> > > debate and coding.
> > >
> > > At present, I have NOT removed anything from [collections].
> > I believe that
> > > there may be people with dependencies on the primitive code
> > there. I do not
> > > plan to release that code however, nor will its prescence block a
> > > [collections] release. I think that this will probably be
> > the position until
> > > [primitives] is ready.
> > >
> > > So... lets try to get [primitives] sorted ;-)
> > >
> > > Stephen
> > >
> > >
> > >
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> >
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