Apple has released Java updates for both Mac OS X 10.6 and Mac OS X 10.5.
Java for Mac OS X 10.6 Update 2 delivers “improved compatibility, security, and reliability by updating Java SE 6 to 1.6.0_20.” This release is only for Mac OS X 10.6.3.
Java for Mac OS X 10.5 Update 7 delivers “improved compatibility, security, and reliability by updating J2SE 5.0 to 1.5.0_24, and updating Java SE 6 to 1.6.0_20 for 64-bit capable Intel-based Macs.” This release is only for Mac OS X 10.5.8.