(from the Java - But Not Coffee department)
(This is a quick post - these instructions are necessarily terse and mainly serve as a reminder to myself. If you do try this - you do so at your own risk - I can't provide any help if you mess anything up.)
I needed to set up Oracle Java JRE 8 on my Ubuntu 12.04 LTS 64-bit system.
For previous versions of Oracle Java, I followed the steps in "6. Installation from RPM package" on the web page here:
These instructions worked fine for previous versions of Java but broke with JRE 8.
When I analyzed the failure, I saw it was breaking with the alternatives command. Ubuntu uses update-alternatives instead of alternatives.
So - I decided to try something bold. I created a symbolic link to alternatives from update-alternatives:
sudo ln -s update-alternatives alternatives
Then, I followed the steps in "6. Installation from RPM package". The package installed properly. Just for reference, here's the commands I used for the JRE 8u77 I installed today:
sudo alien --scripts jre-8u77-linux-x64.rpm
sudo dpkg -i jre1.8.0-77_1.8.077-1_amd64.deb
That left connecting up the Firefox Java plugin. There's many ways to do that, but I like using alternatives.. er... I mean update-alternatives:
sudo update-alternatives --install /usr/lib/mozilla/plugins/libjavaplugin.so libjavaplugin.so /usr/java/default/lib/amd64/libnpjp2.so 20
Obviously - these are for a 64 bit system. These won't work as written for a 32 bit system or a mixed 64/32 bit system.