Re: [gentoo-java] Re: How to predetermine if ebuilds will compile with 1.5?

[David Herron <David.Herron@Sun.COM>]

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Okay, that helps.

I'm not a compiler expert but here's a couple factoids:  1) we're always 
working to improve performance, 2) the compiler team is always working 
on improving the compiler (fix bugs etc), 3) the generated byte codes 
can either exhibit certain bugs or performance gains/losses ... hence, 
hence I expect/assume the byte codes output to vary somewhat from 
release to relase. 

I can't say how much or what specifically that would be.

- David


Caster wrote:
> Greg Tassone wrote:
>   
>> I think this statement is a little too broad to be considered correct.
>> The compiler can (and often does) make changes to the resulting binaries
>> that may be VM-level specific (e.g., targeted for a 1.5 VM).  Consider
>> the "-target" argument for javac, for example, which "Allow[s] javac to
>> use 1.5 specific features in the libraries and virtual
>> machine" (http://java.sun.com/j2se/1.5.0/docs/relnotes/features.html ).
> David Herron wrote:
>   
>> er... Caster, the bytecode does vary based on the compiler.  And the
>> class file format has varied a small amount from release to release with
>> the 1.5 class file format being the most different.
>>
>> This is, as I understand it, the crux of the problem you guys are seeing
>> with adopting 1.5 ... yes?
>
> Sorry, I wasn't clear enough. I didn't mean the class file format which
> is indeed different and causes problems. I was trying to ask if there
> are any (the compiled bytecode performance?) gains of using 1.5 compiler
> for 1.4 source (without specifying --source and --target 1.4). This
> source won't use any 1.5 specific features, but you say the bytecode
> still can somehow?
>
> Caster
>
>   

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