Several people on VT and in other forums have given a list of instructions on how to modify your system so that Java 1.5 (5.0) is the default under OS X. Unfortunately, they forgot to warn you that making such a modification to your system is considered to be a hack by Apple, and while it may appear to work OK now, it can possibly cause serious problems with future system upgrades.

In order to SAFELY make Java 1.5 the default, you should NOT, I repeat, NOT delete or change any system files or symbolic links, but instead use the NON-DESTRUCTIVE methods of:

(1) Modifying your system environment variables for Java, so that the 1.5 command-line tools and applications are found first. You do this by modifying your .profile or .bash_profile and adding these two lines:

export JAVA_HOME="/System/Library/Frameworks/JavaVM.framework/Versions/1.5.0/Home"
export PATH="${JAVA_HOME}/bin:${PATH}"

Now when you type "java -version" at a command prompt, you will get 1.5 as the default, and it will apply in all your terminal sesssions.

(2) For web applications and Java apps that need the VM, use this program to change the default VM that gets used:

'/Applications/Utilities/Java/J2SE 5.0/Java Preferences.app'

Move 1.5 to the top of the listing above 1.4, and it will become the preferred VM. It's just that simple.

Those are the ONLY two things you should do to make 1.5 the default. All other methods that involve deleting files, changing symlinks, etc., are dangerous and should be avoided.

More info about this can be found on MacOSXHints:

http://forums.macosxhints.com/showthread.php?t=47531