My Mac currently is running Snow Leopard (10.6.8), and I would like to develop with Java 7. I downloaded the Java 7 OS X installer from Oracle\'s website, started to run it.
You can build your own one. I did this before. It was easy. And it's as official as you can probably get:
https://wikis.oracle.com/display/OpenJDK/Mac+OS+X+Port