There have been tons of threads/convos on this.

In the early days of Java 7 it was pretty unstable and there was pretty much no convincing reason to use Java 7 over Java 6.

Now that Java 7 has stabilized and Java 6 is EOL it's a reasonable decision to use Java 7 and we do it in production with no issues to speak of.

That being said there was one potential situation we've seen as a community where bootstrapping new node was using 3x more CPU and getting significantly less throughput. However, reproducing this consistently never happened AFAIK.

I think until more people use Java 7 in production and prove it doesn't cause any additional bugs/performance issues Datastax will update their docs. Until now I'd say it's a safe bet to use Java 7 with Vanilla C* 1.2.1. I hope this helps!

Best,
Michael

From: Baron Schwartz <baron@xaprb.com>
Reply-To: "user@cassandra.apache.org" <user@cassandra.apache.org>
Date: Tuesday, February 5, 2013 7:21 AM
To: "user@cassandra.apache.org" <user@cassandra.apache.org>
Subject: Why do Datastax docs recommend Java 6?

The Datastax docs repeatedly say (e.g. http://www.datastax.com/docs/1.2/install/install_jre) that Java 7 is not recommended, but they don't say why. It would be helpful to know this. Does anyone know?

The same documentation is referenced from the Cassandra wiki, for example, http://wiki.apache.org/cassandra/GettingStarted

- Baron