Impact of six month releases

[Stephen Colebourne]

On 3 November 2017 at 09:14, Andrew Haley <aph at redhat.com> wrote:
>> I think this is throwing the baby (Java's long standing backwards
>> compatibility) out with the bathwater (frequent releases), but I'm
>> happy to hear other opinions.
>
> I don't believe that such worries are necessarily justified.
>
> We need to be able to roll back mistakes.  The Java tradition that
> nothing ever gets removed, no matter how much mistaken, holds back
> innovation.  It does this because of a justified fear that if we make
> a mistake, we're stuck with it, so we have to be ultra-cautious.

I think its more than that. Java's success is built on the broader
ecosystem. The JDK itself is an enabler for that. Open source projects
have to be able to produce jar files that work on multiple releases of
the JDK. Things that prevent that are a big issue.

In practical terms I'd argue that:

1) LTS releases define the removal cycle. Code added in a  non-LTS
release (n) can be deprecated in the next non-LTS release (n+1) and
removed in the release after that (n+2). This works because the code
was never in an LTS release. However, code that *was* in the last LTS
release cannot be removed until the release after the next LTS.

eg. code present in 8 cannot be removed until 12 (as 11 is the first
LTS where the deprecation is visible)
eg. code added in 12 can be deprecated in 13 and removed in 14 as 12
and 13 are non-LTS

2) There should be more than 2 security updates for each release.
Without an overlap period, developers are forced to upgrade to the
next release immediately it is GA. This does not reflect real-world
software development practice. If the non-LTS releases are to be used
in production they will need a bare minimum of 4 security updates (one
year) to create a time window overlap with the next release.

3) The javac --release flag should work for at least the last three
LTS releases. A time-window of 10 years would also be about right.
(Its a *really* convenient feature, and if possible I'd prefer it to
never lose support for older versions).

Stephen