https://macmule.com/2013/02/19/getting-java-6-working-on-a-mac-that-has-only-had-java-7-installed/

disableJava7EnableJava6AndDisableXProtect.sh

#!/bin/sh
####################################################################################################
#
# License: https://macmule.com/license/
#
####################################################################################################
#
# Liberally pinched from:
# https://github.com/rtrouton/rtrouton_scripts/tree/master/rtrouton_scripts/re-enable_java_6
# https://github.com/rtrouton/rtrouton_scripts/tree/master/rtrouton_scripts/enable_java_web_plugins_at_login
# http://managingosx.wordpress.com/2013/01/31/disabled-java-plugins-xprotect-updater/
#
####################################################################################################
#
# DEFINE VARIABLES & READ IN PARAMETERS
#
####################################################################################################


# Get logged in users username & home folder path for plist creation later.
loggedInUser=`/bin/ls -l /dev/console | /usr/bin/awk '{ print $3 }'`
loggedInUserHome=`dscl . -read /Users/$loggedInUser | grep  NFSHomeDirectory: | cut -c 19- | head -n 1`

echo "Home Directory for: $loggedInUser, is here: $loggedInUserHome..."


# Get the Macs UUID
if [[ `ioreg -rd1 -c IOPlatformExpertDevice | grep -i "UUID" | cut -c27-50` == "00000000-0000-1000-8000-" ]];
then
    MAC_UUID=`ioreg -rd1 -c IOPlatformExpertDevice | grep -i "UUID" | cut -c51-62 | awk {'print tolower()'}`
elif [[ `ioreg -rd1 -c IOPlatformExpertDevice | grep -i "UUID" | cut -c27-50` != "00000000-0000-1000-8000-" ]];
then
    MAC_UUID=`ioreg -rd1 -c IOPlatformExpertDevice | grep -i "UUID" | cut -c27-62`
fi

echo "This Mac's UUID is: $MAC_UUID..."


# Checks for backup directory for Java 7 plug-in, creating if needed.
if [ -d "/Library/Internet Plug-Ins (Disabled)" ];
then
     echo "Directory /Library/Internet Plug-Ins (Disabled) found. Skipping... "
else
     mkdir "/Library/Internet Plug-Ins (Disabled)"
     chown -R root:wheel "/Library/Internet Plug-Ins (Disabled)"
     echo "Directory /Library/Internet Plug-Ins (Disabled) not found. Creating... "
fi

# Removes previous versions for Java 7 if found in "Internet Plug-Ins (Disabled)"
if [ -d "/Library/Internet Plug-Ins (Disabled)/JavaAppletPlugin.plugin" ];
then
      rm -rf "/Library/Internet Plug-Ins (Disabled)/JavaAppletPlugin.plugin"
      echo "Deleting previous Java 7 plug-in found in /Library/Internet Plug-Ins (Disabled)..."
fi


# Moves current Java 7 plug-in to the backup directory
if [ -d "/Library/Internet Plug-Ins/JavaAppletPlugin.plugin" ];
then
     mv "/Library/Internet Plug-Ins/JavaAppletPlugin.plugin" "/Library/Internet Plug-Ins (Disabled)/JavaAppletPlugin.plugin"
     echo "Moving Java 7 plug-in to /Library/Internet Plug-Ins (Disabled)..."
fi

# Create symlink to the Apple Java 6 plug-in in /Library/Internet Plug-Ins
ln -sf "/System/Library/Java/Support/Deploy.bundle/Contents/Resources/JavaPlugin2_NPAPI.plugin" "/Library/Internet Plug-Ins/JavaAppletPlugin.plugin"
echo "Created symlink for Java 6 plug-in..."

# Re-enable Java SE 6 Web Start, which allows Java applets to run in web browsers
ln -sf "/System/Library/Frameworks/JavaVM.framework/Commands/javaws" "/usr/bin/javaws"
echo "Re-enabled Java SE 6 Web Start..."

# Set the the "Enable applet plug-in and Web Start Applications" setting in the Java Preferences for the current user.
/usr/libexec/PlistBuddy -c "Delete :GeneralByTask:Any:WebComponentsEnabled" "$loggedInUserHome"/Library/Preferences/ByHost/com.apple.java.JavaPreferences.${MAC_UUID}.plist
/usr/libexec/PlistBuddy -c "Add :GeneralByTask:Any:WebComponentsEnabled bool true" "$loggedInUserHome"/Library/Preferences/ByHost/com.apple.java.JavaPreferences.${MAC_UUID}.plist
/usr/libexec/PlistBuddy -c "Delete :GeneralByTask:Any:WebComponentsLastUsed" "$loggedInUserHome"/Library/Preferences/ByHost/com.apple.java.JavaPreferences.${MAC_UUID}.plist
/usr/libexec/PlistBuddy -c "Add :GeneralByTask:Any:WebComponentsLastUsed real $(( $(date "+%s") - 978307200 ))" "$loggedInUserHome"/Library/Preferences/ByHost/com.apple.java.JavaPreferences.${MAC_UUID}.plist

# Delete the JavaAppletPlugin version key from XProtect
/usr/libexec/PlistBuddy -c "Delete :JavaWebComponentVersionMinimum" /System/Library/CoreServices/CoreTypes.bundle/Contents/Resources/XProtect.meta.plist

# Stop XProtect Updating itself
/bin/launchctl unload -w "/System/Library/LaunchDaemons/com.apple.xprotectupdater.plist"

exit 0