Interestingly, Hadoop 3.x will require Java 8 or later. >From http://hadoop.apache.org/docs/r3.0.0-alpha1/ > Minimum required Java version increased from Java 7 to Java 8 > All Hadoop JARs are now compiled targeting a runtime version of Java 8. Users > still > using Java 7 or below must upgrade to Java 8.
Of course, there are still many people using Hadoop 2.x and distributions derived from it, and will be for a while. best, Colin On Mon, Nov 28, 2016, at 11:21, Ismael Juma wrote: > By supporting two Java versions, I mean supporting the two most recent > ones. So, we'd only drop support for Java 7 after Java 9 is released, but > no sooner (independently of how old or unsupported a particular version > is). An alternative approach is to drop support a defined amount of time > after a particular version is EOL'd. > > With respect to the question about the cost of supporting multiple Java > versions: it is OK to compile with the oldest version, but we definitely > need to run the unit, integration, system and performance tests with all > supported versions. The Java team strives to maintain compatibility, but > regressions and behaviour differences are not uncommon across major > releases (and sometimes update releases). Projects like Lucene are very > good at hitting JIT bugs and they actually test against JDK EA snapshot > builds in the hope of triggering them before a stable release. > > Ismael > > On Mon, Nov 28, 2016 at 6:39 PM, radai <radai.rosenbl...@gmail.com> > wrote: > > > i dont completely understand the meaning behind supporting 2 java versions. > > given java's pretty good about backwards compatibility if you build against > > the oldest JDK you support (say 8) it should run on anything newer (say 9). > > what am i missing? > > > > On Mon, Nov 28, 2016 at 4:06 AM, Ismael Juma <ism...@juma.me.uk> wrote: > > > > > I think there are 3 main points that can be taken from that discussion > > with > > > regards to the timing: > > > > > > 1. We should do the switch no earlier than Kafka's next major version > > bump > > > (i.e. 0.11.0.0 at this point) > > > 2. Some would prefer to support two Java versions, so we'd have to wait > > > until Kafka's next major version bump _after_ Java 9 is released. Java 9 > > is > > > currently scheduled to be released in July 2017. I like the guideline of > > > supporting two Java versions at a time, but multiple delays to Java 8 > > and 9 > > > combined with huge improvements in Java 8 could provide the basis for an > > > exception. > > > 3. Some would prefer the clients jar to support Java 7 for longer as > > there > > > are cases where it is hard to upgrade all clients to use Java 8 (maybe > > they > > > run in an older App Server that only supports Java 7, for example). > > > > > > It seems like 1 is a hard requirement while 2 and 3 are less so. Given > > > that, I was planning to restart the conversation when we have a plan to > > > bump Kafka's major version (a message format change would quality > > > typically). > > > > > > Ismael > > > > > > On Thu, Nov 10, 2016 at 7:03 PM, Joel Koshy <jjkosh...@gmail.com> wrote: > > > > > > > http://markmail.org/message/gnrn5ccql7a2pmc5 > > > > We can bump that up to revisit the discussion. That thread didn't have > > > any > > > > closure, but has a lot of background information. > > > > > > > > On Thu, Nov 10, 2016 at 10:37 AM, Sean McCauliff < > > > sean.mccaul...@gmail.com > > > > > > > > > wrote: > > > > > > > > > Wait for JDK 9 which is supposed to be 4-5 months from now? > > > > > > > > > > Sean > > > > > > > > > > On Thu, Nov 10, 2016 at 10:23 AM, radai <radai.rosenbl...@gmail.com> > > > > > wrote: > > > > > > with java 7 being EOL'ed for more than a year and a half now (apr > > > 2015, > > > > > see > > > > > > http://www.oracle.com/technetwork/java/eol-135779.html) i was > > > > wondering > > > > > if > > > > > > there's an official plan/timetable for transitioning the kafka > > > codebase > > > > > > over to java 8? > > > > > > > > > > > > > >
