I had a ton of issues with Java installing minecraft for my kids so maybe I can help. First you can try this:
How to Install Java in OS X Yosemite - that should work and I think its what I had to do to get CityEngine up.
If it doesn't you can try downgrading to Java 6 - what I had to do for Minecraft - How to downgrade Java 7 to Java 6 on Mac OS X - YouTube
Now for the bad news....I've been having some issues with Yosemite, with apparently no known workaround for Yosemite... See my post here - Cannot Browse Computer Directories