Currently Samza builds against JDK 7, although AFAIK we are not yet using JDK7-only language/stdlib features, so we could still support JDK6 if we want to. There have been requests for this:
In June/July there was a mailing list discussion (continued — Apache's mailing list archive doesn't do threading across a month boundary) on which JDK versions to support. There was a general desire to start moving towards JDK8, so that we could start using Java 8 language features and gradually start moving away from Scala. But we can't use Java 8 language features as long as we're still supporting JDK 6 and JDK 7, and the day when everyone is using JDK 8+ still seems fairly far in the future.
JDK 6 was EOL in Feb 2013, but if there is continued demand for it, perhaps we should continue supporting it. The counter-argument is that "JDK6 seems to be becoming the Windows XP of the Hadoop ecosystem", as Jakob Homan put it.
So: should we switch Samza back to building on JDK 6? And if so, can we decide on a policy for removing JDK 6 support?