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From "T Master" <tmas...@iknowledgeinc.com>
Subject Re: javac, depend, and interface constants
Date Mon, 23 Jul 2001 18:11:20 GMT
Would HotSpot have any impact?


----- Original Message -----
From: "Larry V. Streepy, Jr." <streepy@healthlanguage.com>
To: <ant-user@jakarta.apache.org>
Sent: Monday, July 23, 2001 12:03 PM
Subject: Re: javac, depend, and interface constants


> Jason Pettiss wrote:
> >
> > Final constants are hardcoded directly in the classes that use them, for
> > performance reasons.  This is in the java spec (since 1.0).  If you make
a
> > change to the interface/class that defines these constants, but don't
> > recompile the classes that use them, you'll run into *big trouble*.
>
> But these are not final's.
>
> > The javac task fortunately has a 'depend="true"' option, which turns on
> > dependency analysis in the compiler (so that extra files other than
those
> > specified can be brought in and recompiled as needed).  This slows
things
> > down some, but if clean builds are regular practice for you, then you
may
> > want this option.
>
> The depend option on the javac task is essentially useless.  The javac
> task filters the set of files to compile to only those whose source
> modification time is newer than the class file.  Thus, the file is going
> to be compiled regardless of whether any classes it depends upon are
> newer.
>
> The problem lies in determining the reverse dependency: I.e., what
> classes depend on the class that is being compiled.  The depend task
> attempts to do this by reading the class files, but that leads us back
> to the main problem that the compiler is inlining the class member
> reference and, therefore, we lose the dependency. :-(
>
> --
> Larry V. Streepy, Jr.
> Chief Technical Officer and VP of Engineering
>
> Health Language, Inc.  -- "We speak the language of healthcare"
>
> 970/626-5028 (office)           mailto:streepy@healthlanguage.com
> 970/626-4425 (fax)              http://www.healthlanguage.com
>


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