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From Scott Carey <sc...@richrelevance.com>
Subject Re: Java Versions and Hadoop
Date Mon, 10 Oct 2011 04:34:45 GMT


On 10/9/11 9:22 PM, "Scott Carey" <scott@richrelevance.com> wrote:

>
>
>On 10/8/11 11:19 AM, "Ted Dunning" <tdunning@maprtech.com> wrote:
>
>>I hate to sound like the folks who only recently stopped using 1.4, but I
>>am
>>afraid that Todd is right on here.
>>
>>The folks who are desperate for new features are being siphoned off by
>>Scala
>>and Clojure which is leaving a core of recalcitrant termagants like me.
>>I
>>think that it is going to take something as major as the EOL of Java 6 to
>>get big projects to allow code that requires Java 7.
>
>
>That was not the original user's question.  The question was not "When
>will Hadoop REQUIRE Java 7" but "When will Hadoop SUPPORT using a Java 7
>JRE".

Apologies, The quotes were not from the original question -- they were how
I interpreted the question.

>
>
>The JVM in Java 7 is near identical to Java 6.  Sun/Oracle started
>updating the JVM for JRE 6 to lag slightly (6-12 weeks) behind the (then
>in development) Java 7 about 3 years ago.  After the next Java 6 update,
>they will essentially be identical other than a handful of default
>parameters and the presence of the invokevirtual JVM infrastructure.
>The JDK has changed in many ways however -- there may be more risk there
>over the next year than differences in the JVM.
>
>Next, now that Hadoop is using Maven, it would be trivial to create a new
>(optional) module that required Java 7 and provided useful things, like an
>implementation of the new Java 7 File System API for HDFS.  Hadoop would
>not require a Java 7 JRE, but a user that was using a Java 7 JRE would
>have some extra API's available.
>
>Java 8 will be a bigger beast that will likely result in more demands for
>Hadoop to adopt somewhat rapidly.
>Project Lambda will result in many requests for API enhancements around
>Map/Reduce.
>Project Jigsaw may finally rescue Hadoop from itself and allow proper
>isolation of user code from framework code.
>
>
>>
>>On Sat, Oct 8, 2011 at 2:00 AM, Todd Lipcon <todd@cloudera.com> wrote:
>>
>>> I think requiring Java 7 is years off... I think most people have
>>> doubts as to Java 7's stability until it's been adopted by a majority
>>> of applications, and the new features aren't compelling enough to jump
>>> ship, IMO.
>>>
>>> -Todd
>>>
>>> On Fri, Oct 7, 2011 at 3:33 PM,  <Milind.Bhandarkar@emc.com> wrote:
>>> > Hi Folks,
>>> >
>>> > While I have seen the wiki on which java versions to use currently to
>>>run
>>> > Hadoop, I have not seen any discussion about the roadmap of java
>>>version
>>> > compatibility with future hadoop versions.
>>> >
>>> > Recently, Oracle retired the "Operating System Distributor License
>>>for
>>> > Java" (DLJ) [http://robilad.livejournal.com/90792.html,
>>> > http://jdk-distros.java.net/] and Linux vendors have started making
>>> > OpenJDK (6/7) as the default java version bundled with their OSs
>>> > [http://www.java7developer.com/blog/?p=361]. Also, all future Java SE
>>> > updates will be delivered through OpenJDK updates project.
>>> >
>>> > I see that OpenJDK6 (6b20pre) cannot be used to compile hadoop trunk.
>>>Has
>>> > anyone tried OpenJDK7 ?
>>> >
>>> > Additionally, I have a few small projects in mind which can really
>>>make
>>> > use of the new (esp I/O) features of Java 7.
>>> >
>>> > What, if any, timeline do hadoop developers have in mind to make Java
>>>7
>>> as
>>> > required (and tested with OpenJDK 7) ?
>>> >
>>> > Thanks,
>>> >
>>> > - milind
>>> >
>>> > ---
>>> > Milind Bhandarkar
>>> > Greenplum Labs, EMC
>>> > (Disclaimer: Opinions expressed in this email are those of the
>>>author,
>>> and
>>> > do not necessarily represent the views of any organization, past or
>>> > present, the author might be affiliated with.)
>>> >
>>> >
>>>
>>>
>>>
>>> --
>>> Todd Lipcon
>>> Software Engineer, Cloudera
>>>
>


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