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From Chris Nauroth <cnaur...@hortonworks.com>
Subject Re: Moving to JDK7, JDK8 and new major releases
Date Wed, 25 Jun 2014 23:18:36 GMT
I understood the plan for avoiding JDK7-specific features in our code, and
your suggestion to add an extra Jenkins job is a great way to guard against
that.  The thing I haven't seen discussed yet is how downstream projects
will continue to consume our built artifacts.  If a downstream project
upgrades to pick up a bug fix, and the jar switches to 1.7 class files, but
their project is still building with 1.6, then it would be a nasty surprise.

These are the options I see:

1. Make sure all other projects upgrade first.  This doesn't sound
feasible, unless all other ecosystem projects have moved to JDK7 already.
 If not, then waiting on a single long pole project would hold up our
migration indefinitely.

2. We switch to JDK7, but run javac with -target 1.6 until the whole
ecosystem upgrades.  I find this undesirable, because in a certain sense,
it still leaves a bit of 1.6 lingering in the project.  (I'll assume that
end-of-life for JDK6 also means end-of-life for the 1.6 bytecode format.)

3. Just declare a clean break on some version (your earlier email said 2.5)
and start publishing artifacts built with JDK7 and no -target option.
 Overall, this is my preferred option.  However, as a side effect, this
sets us up for longer-term maintenance and patch releases off of the 2.4
branch if a downstream project that's still on 1.6 needs to pick up a
critical bug fix.

Of course, this is all a moot point if all the downstream ecosystem
projects have already made the switch to JDK7.  I don't know the status of
that off the top of my head.  Maybe someone else out there knows?  If not,
then I expect I can free up enough in a few weeks to volunteer for tracking
down that information.

Chris Nauroth
Hortonworks
http://hortonworks.com/



On Wed, Jun 25, 2014 at 3:12 PM, Alejandro Abdelnur <tucu@cloudera.com>
wrote:

> Chris,
>
> Compiling with jdk7 and doing javac -target 1.6 is not sufficient, you are
> still using jdk7 libraries and you could use new APIs, thus breaking jdk6
> both at compile and runtime.
>
> you need to compile with jdk6 to ensure you are not running into that
> scenario. that is why i was suggesting the nightly jdk6 build/test jenkins
> job.
>
>
> On Wed, Jun 25, 2014 at 2:04 PM, Chris Nauroth <cnauroth@hortonworks.com>
> wrote:
>
> > I'm also +1 for getting us to JDK7 within the 2.x line after reading the
> > proposals and catching up on the discussion in this thread.
> >
> > Has anyone yet considered how to coordinate this change with downstream
> > projects?  Would we request downstream projects to upgrade to JDK7 first
> > before we make the move?  Would we switch to JDK7, but run javac -target
> > 1.6 to maintain compatibility for downstream projects during an interim
> > period?
> >
> > Chris Nauroth
> > Hortonworks
> > http://hortonworks.com/
> >
> >
> >
> > On Wed, Jun 25, 2014 at 9:48 AM, Owen O'Malley <omalley@apache.org>
> wrote:
> >
> > > On Tue, Jun 24, 2014 at 4:44 PM, Alejandro Abdelnur <tucu@cloudera.com
> >
> > > wrote:
> > >
> > > > After reading this thread and thinking a bit about it, I think it
> > should
> > > be
> > > > OK such move up to JDK7 in Hadoop
> > >
> > >
> > > I agree with Alejandro. Changing minimum JDKs is not an incompatible
> > change
> > > and is fine in the 2 branch. (Although I think it is would *not* be
> > > appropriate for a patch release.) Of course we need to do it with
> > > forethought and testing, but moving off of JDK 6, which is EOL'ed is a
> > good
> > > thing. Moving to Java 8 as a minimum seems much too aggressive and I
> > would
> > > push back on that.
> > >
> > > I'm also think that we need to let the dust settle on the Hadoop 2 line
> > for
> > > a while before we talk about Hadoop 3. It seems that it has only been
> in
> > > the last 6 months that Hadoop 2 adoption has reached the main stream
> > users.
> > > Our user community needs time to digest the changes in Hadoop 2.x
> before
> > we
> > > fracture the community by starting to discuss Hadoop 3 releases.
> > >
> > > .. Owen
> > >
> >
> > --
> > CONFIDENTIALITY NOTICE
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> to
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> >
>
>
>
> --
> Alejandro
>

-- 
CONFIDENTIALITY NOTICE
NOTICE: This message is intended for the use of the individual or entity to 
which it is addressed and may contain information that is confidential, 
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of this message is not the intended recipient, you are hereby notified that 
any printing, copying, dissemination, distribution, disclosure or 
forwarding of this communication is strictly prohibited. If you have 
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