Yes, it's perfectly OK to install Java 7 on Ubuntu. In fact, you can install and use multiple versions of Java, from multiple vendors, at the same time!

The reasons some don't recommend Java 7 as a replacement for Java 6 yet, for end-users, include:

• Java 7 is still relatively new and "maturing"


• Most of the Java apps/code out there was written for Java 6 and works perfectly with it


• Java 7 should be able to run the above too, but rarely there's a bug and it fails or causes problems.

As this link from May 2012 explains, while Java 7 has been available for developers since mid-2011, Oracle only started upgrading Windows users to Java 7 in May 2012, and it is still offering and recommending Java 6 to Linux and Mac users.

Bottom-line: if you are a developer, get Java 7. If you are a user, you can get it too but keep Java 6 around. This question explains how you can install multiple Java versions and use a graphical utility to chose which is the "default" Java