How does one tell if a Mac's processor is 32-bit or 64-bit?
And why update Java...
QUOTE
This Java for Mac OS X 10.5 Update 1 adds Java SE 6 version 1.6.0_05 to your Mac. This update does not replace the existing installation of J2SE 5.0 or change the default version of Java.
Presumably one has to find the old version and manually replace it with the new one. Whatever for? Most updates are installed automagically.