Tale of installing RM6 on Mac OS 10.8.5
Double-clicking on the RM6 icon made it bounce on the dock. That's all. The Mac System Preferences/Java panel did not show a Java release.
My Java expert discovered that Java 6 and Java 7 were both installed and were conflicting. (Why didn't the latest release tell me about that? Why didn't it erase Java 6? Steve, we miss you.) Anyway, I removed Java 6 but RM6 remained dead. Then, on the Oracle site, we downloaded (and installed) jdk-7u45-macosx-x64.dmg. It worked. System Preferences said "Java 7 update 45." RM6 came to life.