Accelerating the JDK LTS release cadence

[mark.reinhold at oracle.com]

2021/9/14 8:12:11 -0700, Remi Forax <forax at univ-mlv.fr>:
> As a user, i applaud the idea of having more choices but i've some
> concerns:
> 
> - as a maintainer of some libraries, it will make my life more
> complex, because the ecosystem will not evolve in lockstep as it was
> before, i fear a scenario like Android were numerous LTS are used at
> the same time by different people making the choice when to upgrade
> quite complex.

There is already a vast range of releases in use today -- including
releases earlier than JDK 8.  The ecosystem has never evolved in
lockstep.

I agree that it’s likely that there will be more LTS releases in active
use than there are today.  Thanks to changes we started making years
ago, however, in particular the encapsulation of JDK internals [1], I
don’t think that will be a big problem.  Many library maintainers have
found that once they move past JDK 8 it’s pretty easy to keep up with
every six-month feature release, LTS or not.

As a library maintainer you can choose a baseline JDK release depending
upon the new features you want to use, and then stick to building with
that baseline for years if you like.  During that time, just make sure
that it continues to run on the latest LTS release while still building
with the baseline.  Even better: Spread your effort out over time, and
give your users the option of using non-LTS releases, by tracking every
six-month feature release instead.

> - as an OpenJDK member, we now that LTS has an impact of the
> development of the JDK, stewards are less available before a LTS,
> there are more migration documentations to write etc, so for me this
> proposed change will slow down the OpenJDK development not accelerate
> it.

My perspective from inside Oracle is that most of us working on JDK 17
itself have spent hardly any more time on it at all as compared to the
preceding non-LTS releases.  We’ve been writing release notes, updating
migration guides and other documentation, and so forth for every single
six-month feature release.  Do you have evidence to suggest that we’ve
been less available?

> - some people will start to think in term of feature releases again
> when big features like Loom or Valhalla will land. I'm ok with a LTS
> without a big feature or a LTS with more than one big features but i
> fear that not everybody will agree on that. A 3 years is a long time,
> that shield us from that kind of discussions.

People who want big features to align with LTS releases are, in effect,
arguing for a return to the old unpredictable feature-driven release
model.  We abandoned that model in 2017.  Do you want to go back?

There will always be discussions about which features are, or are not,
or should be, or shouldn’t be, in a particular release.  Let’s not be
unduly distracted by them.

- Mark


[1] https://openjdk.java.net/jeps/403