HOWTO Install Sun's JAVA on Ubuntu Lucid Lynx (10.04)
After Ubuntu's decision to default to OpenJDK for 10.04 (which is a good decision, IMHO), Sun's (but is it still Sun, or Oracle?) JAVA somewhat "disappeared" from Ubuntu (multiverse).
That being said, some people may still need features only available in Sun's JRE/JDK, which might not yet have been Freed.
Actually, Ubuntu is still shipping it, but in its "partner" section.