It seems that JINI is pretty much an abandoned project. The latest release from the Jini.org site is from last year, and there has been no news since then.
JINI appears
Jini didn't fail due to a lack of need. There were problems with:
By the time the licensing was sorted out it was too late. The moment had passed.
It's a brilliant idea, and Bill Joy's a genius, but like a lot of great technologies it simply didn't catch on. The marketplace didn't adopt it.
Jini didn't disappear. As you've noted, it's still available. The adoption rate hasn't been high because it isn't scratching anybody's itch.