How to upgrade from java6 to java7 on 10.04?

[Jim Byrnes]

Firefox popped up a warning yesterday that Java6 had security problems 
and should be upgraded to Java7. I googled upgrading to Java7 and found 
various answers ranging from giving step by step manual instructions to 
recommending using ppa/webup8.

My concern is they all seemed to focus on installing Java7 but I didn't 
see anything about upgrading.  What happens to my Java6 installation?
Just looking for a smooth, hassle free way to get secure java running again.

Thanks,  Jim