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Date: Thu, 15 Jan 2015 17:42:43 +0100
From: Luc Maisonobe <luc@spaceroots.org>
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To: Commons Developers List <dev@commons.apache.org>
Subject: Re: [Math] Java version
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Le 15/01/2015 17:15, Gilles a écrit :
> On Thu, 15 Jan 2015 07:52:11 -0500, Hank Grabowski wrote:
>> Good call, Silviu!
>>
>> The most recent version of their survey of Plumbr installations (823 in
>> total) was May of last year, only a few months after Java 8 came out
>> (link
>> below).  At that time the break down was: Java 5 at 0.4%, Java 6 at 36%,
>> Java 7 at 61% and Java 8 at 2.5%.  I'm still looking for more data on
>> this,
>> but Rebel Labs has a similar article (not broken down by version) that
>> showed that 65% of development was on Java 7 by May of last year too. I
>> doubt the balance was Java 8 at that point, so there must be a sizable
>> Java
>> 6 contingent still.
>>
>> One other thing that came to mind with the new Java 8 features is how
>> that
>> is supported on Android.  As far as I can tell Android KitKat, as well as
>> the latest release of the Android Studio and SDK Tools doesn't support
>> Java
>> 8 yet.  In fact, according to the Android development setup page versions
>> between (and including) Gingerbread and KitKat require JDK 6, not 7.  I
>> haven't coded Android recently to know whether it does work on JDK 7
>> or if
>> is just a requirement but it is peculiar that the main instructions call
>> for JDK 7 installation and then the footnote specifically tells
>> developers
>> to pull a different JDK version for those earlier platforms.  I can't
>> tell
>> where the Java 7 language features were added to Android before the
>> current
>> version, Lollipop.  I was surprised Lollipop wasn't on their dashboard
>> but
>> according to the AppBrain statistics it accounts for far less than 1% of
>> the installed phones.  So best case scenario would be Jelly Bean
>> supports 7
>> (no indication that's true), which means 85% of Android devices would be
>> covered if we set a Java 7 minimum.  Next best would be KitKat (more
>> likely
>> but not according to the install instructions) which means 39%.  As for
>> Java 5, that was needed for pre-Gingerbread Android OS which accounts for
>> 0.5% of the market.
>>
>> I guess with all of that it's clear that Java 5 is unnecessarily being
>> maintained at this point.  Both surveys of servers and Android show far
>> less than 1% usage.  It seems Java 6 penetration may be still be pretty
>> substantial, even conservatively at on the order of 25% (if Java 7 and 8
>> adoption picked up dramatically in 6 months after the surveys as I
>> imagine
>> it did to some extent).  So it seems the most reasonable conservative
>> play
>> would be to stick with Java 6, especially if we can confirm that between
>> half to 85% of Android devices can't use Java 7 language features.  A
>> more
>> aggressive play would be to set a requirement for Java 7.  Setting the
>> minimum at Java 8 at this time seems overly aggressive at this time
>> though.
>>
>> https://plumbr.eu/blog/most-popular-java-environments-in-2014
>>
>> http://pages.zeroturnaround.com/Java-Tools-Technologies.html
>>
>> http://source.android.com/source/initializing.html
>>
>> https://developer.android.com/about/dashboards/index.html
>>
>> http://www.appbrain.com/stats/top-android-sdk-versions
> 
> I wonder: Isn't the "end of public updates"[1] (scheduled on April of
> this year for Java 7) somehow going to change that picture a lot?
> If not, why?

I don't think so. If you take the use case Hank pointed out (Android
phones), many people want to be able to add new apps at will, but only a
smaller number will change the system completely and the JVM that comes
with it. And yes, there are Android applications that use Apache Commons
Math (and Orekit ;-).

best regards,
Luc

> 
> 
> Regards,
> Gilles
> 
> [1] http://www.oracle.com/technetwork/java/eol-135779.html
> 
> 
>>
>> On Wed, Jan 14, 2015 at 11:20 PM, Silviu Burcea
>> <silviuburceadev@gmail.com>
>> wrote:
>>
>>> I think Rebel Labs or Plumbr have some metrics about JDK usage.
>>>
>>> On Wed, Jan 14, 2015 at 10:21 PM, Hank Grabowski
>>> <hank@applieddefense.com>
>>> wrote:
>>>
>>> > Java 8 has only been out for less than a year.  There is still a
>>> sizable
>>> > percentage of groups that have not converted up to Java 8 for myriad
>>> > reasons.  While I was surprised that we are requiring backwards
>>> > compatibility with the ten year old Java 5 I think jumping all the
>>> way to
>>> > requiring Java 8 may be a bit too much of a stretch.  I would vote
>>> for a
>>> > minimum required version of Java 7 with the ability to run in Java
>>> 8.  I
>>> > wish I could find metrics to quantify the penetration of each of the
>>> JDKs,
>>> > but my gut says Java 7 would a reasonable cutoff.
>>> >
>>> > On Tue, Jan 13, 2015 at 8:31 PM, Gilles <gilles@harfang.homelinux.org>
>>> > wrote:
>>> >
>>> > > Raising this issue once again.
>>> > >>> Are we going to upgrade the requirement for the next major
>>> release?
>>> > >>>
>>> > >>>  [ ] Java 5
>>> > >>>  [ ] Java 6
>>> > >>>  [ ] Java 7
>>> > >>>  [ ] Java 8
>>> > >>>  [ ] Java 9
>>> > >>>
>>> > >>
>>> > > Counts up to now:
>>> > >
>>> > > Java 7      -> 2
>>> > > Java 7 or 8 -> 2
>>> > > Java 8      -> 2
>>> > >
>>> > > Any more opionions?
>>> > >
>>> > > Gilles
> 
> 
> 
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