You should already have it.
Update 10, 29 June 2011 - This release updates J2SE 5.0 to 1.5.0_30, and updates Java SE 6 to 1.6.0_26. J2SE 1.4.2 is no longer being updated to fix bugs or security issues and remains disabled by default in this update. Support for out-of-process Java applets on Mac OS X 10.5 Leopard has been removed with this update.
This release is only for Mac OS X 10.5.8 or later versions of Mac OS X 10.5. http://support.apple.com/kb/DL1359
and for Snow Leopard:
Note: Java 1.6 for Leopard is 64 bit only, but for Snow Leopard it is available for both 32 and 64 bit.
But since August 2012 updates for Java (and especially Java Runtime Environment, which is what you actually need) must now be downloaded direct from Oracle:
Further information here:
Hi Klaus, a few days ago Apple did some changes, I updated my Mountain Lyon and now cannot run a whole bunch of applications and applets that are Java related, and, I cannot seem to uninstall Java 7 and return to Java 6, cant even find my Java Preferences utility...Do you know how I can uninstall the latest Mountain Lyon update, or Mountain Lyon (and Lyon) itself? I need Java working...
Addition to y previous post:
However, if you need the Jave 6 JRE and plug-in, MadMAC0 has posted at
Apple has also posted (Oct 22/12) the approved solution for restoring the Java 6 plug-in: