
The Java runtime shipping in Mac OS X 10.6 Snow Leopard, and Mac OS X 10.5 Leopard, will continue to be supported and maintained through the standard support cycles of those products. 'This means that the Apple-produced runtime will not be maintained at the same level, and may be removed from future versions of Mac OS X. 'As of the release of Java for Mac OS X 10.6 Update 3, the version of Java that is ported by Apple, and that ships with Mac OS X, is deprecated.' The most significant change is documented in the developer release notes. Java Plug-in 1.5.0 Using JRE version 1.5.016 Java HotSpot (TM) Client VM MRJ Plugin for Mac OS X v1.0.1 starting up Java Applet Security Fri Feb 06 23:47: : Bad version number in. If you have Java 7 or later versions, you will see a Java icon under System Preferences. To get the latest Java from Oracle, you will need Mac OS X 10.7.3 and above. Mac OS X 10.7 (Lion) and above: Java is not pre-installed with Mac OS X versions 10.7 and above. However, those are not the most interesting items about this release. Mac OS X 10.6 and below: Apple's Java comes pre-installed with your Mac OS.

The general release notes are here and the security fixes are listed here. Apple released Java for Mac OS X 10.6 Update 3 (and a corresponding Java for Mac OS X 10.5 Update 8) through Software Update shortly after the Back to the Mac event.
