in February 2012 Apple renamed "Mac OS X" to "OS X".
So starting with Mountain Lion (10.8), the operating system is called "OS X" and not "Mac OS X".

At the certified system config pages for Java 7 and 8 we should correct that:

http://www.oracle.com/technetwork/java/javase/config-417990.html
http://www.oracle.com/technetwork/java/javase/certconfig-2095354.html

For a fix suggestion please have a look at the image that is attached to this bug report.

References:
http://www.apple.com/osx/
http://en.wikipedia.org/wiki/OS_X
http://www.theverge.com/2012/2/16/2802281/apple-officially-renames-mac-os-x-to-os-x-drops-the-mac