Installing Oracle Java in Ubuntu, Something I seem to do a lot!
I create Virtual Box Virtual Machines for just about every project, so I end up installing Java on them a lot. I like the Oracle JDK, but for licensing reasons, that install is not available as part of the "normal" apt repository.
I installed Java via a PPA (http://askubuntu.com/questions/4983/what-are-ppas-and-how-do-i-use-them) by webupd8team (http://www.webupd8.org/2012/01/install-oracle-java-jdk-7-in-ubuntu-via.html). I ran these commands to add the PPA to the apt-get repo and update that repo, install Java7, and set up the various java 7 environment variables.
add-apt-repository ppa:webupd8team/java
apt-get update
apt-get install oracle-java7-installer
apt-get install oracle-java7-set-default