Script to hot switch JDK versions in Mac OS X terminals

Personal note.

Here is a script that lets you switch your JDK version in a terminal window. It also has auto completion.

Put the script in a file and add

source filename

in ~/.profile or ~/.bash_profile and you will be able to call setjdk and use autocompletion (with <tab>) from the command line.

emmanuel@computer $ setjdk 1.<tab>

emmanuel@computer $ setjdk 1.5

Original version at codehaus.

#!/bin/bash

function defaultjdk {

local vmdir=/System/Library/Frameworks/JavaVM.framework/Versions

local ver=${1?Usage: defaultjdk }

[ -z "$2" ] || error="Too many arguments"

[ -d $vmdir/$ver ] || error="Unknown JDK version: $ver"

[ "$(readlink $vmdir/CurrentJDK)" != "$ver" ] || error="JDK already set to $ver"

if [ -n "$error" ]; then

echo $error

return 1

fi

echo -n "Setting default JDK & HotSpot to $ver ... "

if [ "$(/usr/bin/id -u)" != "0" ]; then

SUDO=sudo

fi

$SUDO /bin/rm /System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK

$SUDO /bin/ln -s $ver /System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK

echo Done.

}

function setjdk {

local vmdir=/System/Library/Frameworks/JavaVM.framework/Versions

local ver=${1?Usage: setjdk }

[ -d $vmdir/$ver ] || {

echo Unknown JDK version: $ver

return 1

}

echo -n "Setting this terminal's JDK to $ver ... "

export JAVA_HOME=$vmdir/$ver/Home

PATH=$(echo $PATH | tr ':' '\n' | grep -v $vmdir | tr '\n' ':')

export PATH=$JAVA_HOME/bin:$PATH

java -version

}

function _setjdk_completion (){

COMPREPLY=()

local vmdir=/System/Library/Frameworks/JavaVM.framework/Versions

local cur=${COMP_WORDS[COMP_CWORD]//\\\\/}

local options=$(cd $vmdir; ls | grep 1. | tr '\n' ' ')

COMPREPLY=($(compgen -W "${options}" ${cur}))

}

complete -F _setjdk_completion -o filenames setjdk

complete -F _setjdk_completion -o filenames defaultjdk