[gentoo-user] Emerging java with gcj

[gentoo-user] Emerging java with gcj

[Florian Philipp]

Hi!

I've noticed that the gcj use flag is not enabled by default and 
therefore all java code is compiled to byte code instead of native 
binaries, am I correct?

I wonder how I can change that. Just re-emerge gcc with USE="gcj" and 
all packages containing java code? Is it even a good idea?
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Re: [gentoo-user] Emerging java with gcj

[Randy Barlow]

Florian Philipp wrote:
> I've noticed that the gcj use flag is not enabled by default and
> therefore all java code is compiled to byte code instead of native
> binaries, am I correct?

gcj can compile java code directly to machine code, and I'm pretty sure
that the Sun compiler just compiles to byte code.  I have no experience
with gcj though, so I can't answer your second question...

> I wonder how I can change that. Just re-emerge gcc with USE="gcj" and
> all packages containing java code? Is it even a good idea?


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Randy Barlow
http://electronsweatshop.com
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Re: [gentoo-user] Emerging java with gcj

[Kevin O'Gorman]

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On 10/14/07, Randy Barlow <randy@electronsweatshop.com> wrote:
>
> Florian Philipp wrote:
> > I've noticed that the gcj use flag is not enabled by default and
> > therefore all java code is compiled to byte code instead of native
> > binaries, am I correct?
>
> gcj can compile java code directly to machine code, and I'm pretty sure
> that the Sun compiler just compiles to byte code.  I have no experience
> with gcj though, so I can't answer your second question...
>
> > I wonder how I can change that. Just re-emerge gcc with USE="gcj" and
> > all packages containing java code? Is it even a good idea?


Probably not, but you could always try it and report back to the list... :o)

Nothing that needs to work with a class loader, like applets do, will work.
I would expect some problems with introspection.  Moreover, last I tried it,
there were buckets of incompatibility with the Java libraries.  Maybe it's
more mature now.

Kevin O'Gorman, PhD

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Re: [gentoo-user] Emerging java with gcj

[Hans-Werner Hilse]

Hi,

On Thu, 11 Oct 2007 13:59:23 +0200
Florian Philipp <f.philipp@addcom.de> wrote:

> I've noticed that the gcj use flag is not enabled by default and 
> therefore all java code is compiled to byte code instead of native 
> binaries, am I correct?

I think the gcj flag toggles if java support is added at all.
gcj itself can compile to bytecode (class files) or native binary code.
In order to generate java bytecode, the flag "-C" has to be specified.

> I wonder how I can change that. Just re-emerge gcc with USE="gcj" and 
> all packages containing java code? Is it even a good idea?

It will take a lot more time when emerging gcc. Whether you need it
depends on what you are planning to do with it... If you just need a
full blown JDK, the gcj might not be exactly what you want.

Gcj also brings the gij interpreter, which can be used to run java
bytecode.

-hwh
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