Apple updates Java for Snow Leopard and Leopard
Apple just released a Java update today, bring improvements to Java in Mac OS X. Java for Mac OS X 10.6 Update 1 for Snow Leopard updates Java SE 6, while Java for Mac OS X 10.5 Update 6 updates J2SE 5.0 and Java SE 6. Both of these updates improve reliability, security, and compatibility for Java.
The Java for Mac OS X 10.5 Update 6 update also disables J2SE 1.4.2, as it's no longer being updated to fix issues.
These updates can be downloaded with Software Update, or from the Apple Support Downloads page.