HT1338: OS X: Updating OS X and Mac App Store appsLearn about OS X: Updating OS X and Mac App Store apps
Currently Being ModeratedOct 3, 2012 10:29 AM (in response to GBJCAM)
Look for JavaPreferences.app in Applications>Utilities. I think I remember Apple disabling the Safari Java plugin for security reasons in a relatively recent 10.5 update.
To improve the security of your Mac, this update also disables the Java plug-in in Safari. For instructions on how to re-enable it, please visit: http://support.apple.com/kb/HT5241.