I'm not sure if this is in the right spot (if not I apologize), but I figure it is because this relates directly to building Android.
When I upgraded to Ubuntu 12.04, all the sudden I couldn't install Java (sha256sum mismatch jdk-7u3-linux-x64.tar.gz), which means I can't do much deving. Well I searched through the interweb and finally found a solution.
By now, you have probably gotten an error and the terminal has stated that Java was not installed. No problem.
Download Java directly from Oracle:
Now, move what you just downloaded to /var/cache/oracle-java7-installer/
Now scroll down and find the following:
Now put a # next to each line between "Downloading..." and "Downloading done."
Save, and go back to your terminal.
Java should now install properly.
(most helpful info is in the comments)