OpenJDK vs Sun JDK Versions

[Dalibor Topic]

Keith Kowalczykowski wrote:
> Either way, its somewhat disconcerting that OpenJDK is being pushed by all
> of the major distros, but does not have the same set of patches/bugfixes as
> Sun's own JDK.

Fwiw, next to no software in any distribution has precisely the same set of 
patches/bugfixes as the same software in another distribution. 

That's a feature of the Linux distribution model - different distributions 
release on different cycles and therefore they will most likely include 
different patches. In addition, they tend to focus on different niches, 
as well, which gives additional incentive to include some patches and not 
to include others.

> Furthermore, there is no easy way of telling what comparable
> Sun JDK that OpenJDK is currently targeting, or whether a bug in the Sun JDK
> has even been fixed in OpenJDK.

Actually, there is - OpenJDK 6 is targeting JDK 6. OpenJDK is targeting JDK 7.

Beyond that, a simple way to figure out whether a change has been included in
one of the two is to 

for i in `hg ftrees`; do echo "checking " $i ; hg -R $i log -k $bug_id ; done

in a checked out repo.

> As the adoption of OpenJDK has accelerated
> in the major distros, I think Sun should strongly reconsider this
> forked-approach, as it causes major headaches for developers/sysadmins.

If you're interested in helping out with the backporting work,
I think it may be possible to write a script that looks at the
OpenJDK 7 changesets automatically and tries to apply them, if the
changeset applies cleanly proceeds to build OpenJDK 6 from scratch, if 
it builds with no new warnings or errors then proceeds to run the regression test 
suite and to compare the regression test results with the known ones for 
the previous good status, and if there are no newly introduced regressions
then checks if the publicly visible API has been changed, and if it hasn't 
proceeds to notify our bugzilla of a backporting candidate changeset.

Whether a changeset gets applied depends on other factors, too, 
of course - given the stability goals of OpenJDK 6, we'll likely be a lot 
more conservative then a script's results would allow for, but it would
be a good first pass to weed out trivial backporting candidates.

Interested?

cheers,
dalibor topic
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