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From Haohui Mai <h...@hortonworks.com>
Subject Re: Plans of moving towards JDK7 in trunk
Date Fri, 04 Apr 2014 23:22:26 GMT
bq. It might not be as clear cut...

Totally agree. I think the key is that we can do the work in an incremental
way. We can only introduce JDK7 dependency on the server side. In order to
do this we need to separate the client-side code to separate jars. I've
already proposed to create a hdfs-client jar in the hdfs-dev mailing list.

bq.  I would have thought it could be easily achieved by marking certain
project poms with source/target 1.6 in their maven compiler plugin
configuration while upgrading the default setting to 1.7. Do you anticipate
more issues?

Correct me if I'm wrong, but I think that's enough. The work should be
minimal.

~Haohui

On Fri, Apr 4, 2014 at 3:43 PM, Sangjin Lee <sjlee@apache.org> wrote:

> Please don't forget the mac os build on JDK 7. :)
>
>
> On Fri, Apr 4, 2014 at 3:15 PM, Haohui Mai <hmai@hortonworks.com> wrote:
>
> > I'm referring to the later case. Indeed migrating JDK7 for branch-2 is
> more
> > difficult.
> >
> > I think one reasonable approach is to put the hdfs / yarn clients into
> > separate jars. The client-side jars can only use JDK6 APIs, so that
> > downstream projects running on top of JDK6 continue to work.
> >
>
> It might not be as clear cut. For clients to run clean on JDK 6, not only
> the client projects/artifacts but also any of their dependencies must be
> free of JDK 7 code. And this obviously includes things like hadoop-common
> (or any downstream dependencies for that matter).
>
>
> >
> > The HDFS/YARN/MR servers need to be run on top of JDK7, and we're free to
> > use JDK7 APIs inside them. Given the fact that there're way more code in
> > the server-side compared to the client-side, having the ability to use
> JDK7
> > in the server-side only might still be a win.
> >
> > The downside I can think of is that it might complicate the effort of
> > publishing maven jars, but this should be an one-time issue.
> >
>
> Could you elaborate on why it would complicate maven jar publication?
> Perhaps I'm over-simplifying things, but I would have thought it could be
> easily achieved by marking certain project poms with source/target 1.6 in
> their maven compiler plugin configuration while upgrading the default
> setting to 1.7. Do you anticipate more issues?
>
>
> >
> > ~Haohui
> >
> >
> > On Fri, Apr 4, 2014 at 2:37 PM, Alejandro Abdelnur <tucu@cloudera.com
> > >wrote:
> >
> > > Haohui,
> > >
> > > Is the idea to compile/test with JDK7 and recommend it for runtime and
> > stop
> > > there? Or to start using JDK7 API stuff as well? If the later is the
> > case,
> > > then backporting stuff to branch-2 may break and patches may have to be
> > > refactored for JDK6. Given that branch-2 got GA status not so long
> ago, I
> > > assume it will be active for a while.
> > >
> > > What are your thoughts on this regard?
> > >
> > > Thanks
> > >
> > >
> > > On Fri, Apr 4, 2014 at 2:29 PM, Haohui Mai <hmai@hortonworks.com>
> wrote:
> > >
> > > > Hi,
> > > >
> > > > There have been multiple discussions on deprecating supports of JDK6
> > and
> > > > moving towards JDK7. It looks to me that the consensus is that now
> > hadoop
> > > > is ready to drop the support of JDK6 and to move towards JDK7. Based
> on
> > > the
> > > > consensus, I wonder whether it is a good time to start the migration.
> > > >
> > > > Here are my understandings of the current status:
> > > >
> > > > 1. There is no more public updates of JDK6 since Feb 2013. Users no
> > > longer
> > > > get fixes of security vulnerabilities through official public
> updates.
> > > > 2. Hadoop core is stuck with out-of-date dependency unless moving
> > towards
> > > > JDK7. (see
> > > > http://hadoop.6.n7.nabble.com/very-old-dependencies-td71486.html)
> > > > The implementation can also benefit from it thanks to the new
> > > > functionalities in JDK7.
> > > > 3. The code is ready for JDK7. Cloudera and Hortonworks have
> successful
> > > > stories of supporting Hadoop on JDK7.
> > > >
> > > >
> > > > It seems that the real work of moving to JDK7 is minimal. We only
> need
> > to
> > > > (1) make sure the jenkins are running on top of JDK7, and (2) to
> update
> > > the
> > > > minimum required Java version from 6 to 7. Therefore I propose that
> > let's
> > > > move towards JDK7 in trunk in the short term.
> > > >
> > > > Your feedbacks are appreciated.
> > > >
> > > > Regards,
> > > > Haohui
> > > >
> > > > --
> > > > CONFIDENTIALITY NOTICE
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> > > > of this message is not the intended recipient, you are hereby
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> > >
> > >
> > >
> > > --
> > > Alejandro
> > >
> >
> > --
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-- 
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, 
privileged and exempt from disclosure under applicable law. If the reader 
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 
received this communication in error, please contact the sender immediately 
and delete it from your system. Thank You.

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