Bug#212863: java-common: New java policy including tools to manage the changes

["T. Alexander Popiel" <popiel@wolfskeep.com>]

In message:  <[🔎] 1065555500.32697.11.camel@sarge>
             Ean Schuessler <ean@brainfood.com> writes:

>I still don't like the findjava idea. What is the goal? It looks like
>this script provides a common interface to all of the java execution
>systems (compilers, JITs, interpreters or otherwise) by concentrating
>shell script adapters into a single file. I think it is much more
>maintainable to define the calling conventions and then require each
>system (in the language of its choice) to provide a "java" file that
>provides the common calling convention.
>
>With the findjava script it looks like I would need to submit a patch
>anytime Kaffe's command line conventions changed rather than just fixing
>an adaptor that resides in my own package.

I think there are two goals:

1) Standardize the invocation interface, so that it is feasible to have
   java packages that will have a hope of running on a VM that the
   packager did not directly support.

2) Localize the invocation interface, so that the hunt-and-find-a-good-VM
   logic isn't replicated in all the myriad java packages.

This is all to make it easier on the packagers of end-user java programs,
not to make it easier for the VM, compiler, etc packagers.

I think that you are right in your assessment of needing to submit a
patch to findjava whenever Kaffe's command line changes, and I agree that
this is suboptimal.  I also think it would be good to define a standard
interface that packages like Kaffe could support, but I do not think that
is sufficient, because we cannot hope to get Sun (or any of the other
proprietary vendors) to conform to that standard.  For them, we need
something external like findjava.  (Simply ignoring Sun and the other
non-free java implementations is not really an option... that'll just
alienate our users who need some feature that hasn't yet made it into
one of the free VMs.)

If we both define an standard interface for the nicely packaged
implentations, and make findjava use that interface when possible
(but still have special-case foo for the unpackageables like Sun's),
then I think that we'll come as close as possible to the best of both
worlds.

- Alex