To switch JAVA_HOME in the current YADR zsh shell on a mac put this file in .zsh.after

setJavaHome.zsh

function setJavaHome
{
    javaVersions=($(/usr/libexec/java_home -V 2>&1 | grep x86 | awk -F ":" '{print $1}' | awk -F "," '{print $1}' | xargs echo -n))

    newJava=""
    while [[ $newJava = "" ]]; do
        echo "Select your Java version for this shell"
        select newJava in ${javaVersions[@]}; do
            if [[ $newJava = "" ]]; then
                echo "Please enter a valid option."
            else
                export JAVA_HOME=$(/usr/libexec/java_home -v $newJava)
                echo $(java -version)
            fi
            break
        done
    done
}

Should work in a bash profile too, but you might have to change line 3 to be:
read -a javaVersions <<<$(/usr/libexec/java_home -V 2>&1 | grep x86 | awk -F ":" '{print $1}' | awk -F "," '{print $1}' | xargs echo -n)