Brad, Tim, Al and Steve,
I asked on an OSX Java list about having multiple Java versions on an
OSX machine. See
<http://lists.apple.com/mhonarc/java-dev/msg41909.html> and responses,
if you're interested.
In summary, you can't choose which JDK you have.
The reason that the JDK is (relatively) portable to other unixes is
that such ports tend to use only the traditional unix OS API (POSIX
plus a _few_ OS-specific twiddly bits); in alignment with Apple
traditions, and to support better graphics performance, presumably, the
OSX Java port freely uses a much larger OS API (in `system frameworks',
I think), not all of which is public or stable between OS releases. In
OSX terminology, Java is a System Framework, and thus part of the OS,
as opposed to being just another application. As a direct consequence,
JDK versions are tied to very specific OS releases.
Thus up to OSX 10.3.2 or thereabouts, you had 1.4.1; in 10.3.3 or
10.3.4, this was upgraded to 1.4.2. 10.3 also supports JDK 1.3 for
legacy reasons, with a particular supported procedure for switching
between them. It's anyone's guess what we'll get in 10.4: maybe 1.5,
maybe 1.5+1.4.
See you,
Norman
--
----------------------------------------------------------------------
Norman Gray / Physics and Astronomy, University of Glasgow, UK
http://www.astro.gla.ac.uk/users/norman/
|