I know that I can download it, but I want to if the available version the stable and final version. Stable and final are relative. I'm sure there will eventually be a 5.1, and probably a 5.2, and maybe more, before they eventually move on to 6.0 or whatever they decide to call the next one. But the official release of 5.0 is what's available now. It's not a beta, not a "release candidate". It is
the official 5.0 release. So download it. Upgrading later is not going to be a big deal.
Sun reverted to JDK rather than SDK because JDK is what they called it for years, and even after Sun changed it to SDK, many of us continued to refer to it as JDK. So now we've finally won.