Here's the script that I use on macosx to switch JDKs in consoles. It can easily be adapted for any unixish system.

export JDK=/System/Library/Frameworks/JavaVM.framework/Versions/$1/Home/

if [[ -d $JDK ]] then echo "using $JDK as the current jdk..." export JAVA_HOME=$JDK export PATH=$JAVA_HOME/bin:$PATH else echo "setjdk error: $JDK directory does not exist" fi

Use it like . setjdk 1.4.2, don't forget the initial dot and space which mean "execute this script without starting a new process", so that the JAVA_HOME and PATH defined in the script are valid for your current shell.

Thanks Helma for asking about this, it's good to know that this entry can actually be useful to some people, as opposed to just noise ;-)