Posting install_apple_java_on_demand script

For Mac OS X 10.7.x and higher, there's a way to override the install
check that softwareupdate uses which is specific to Apple's Java
updates. By setting the JAVA_INSTALL_ON_DEMAND environment variable for
softwareupdate, you can force softwareupdate to install the latest Java
update from Apple. This script takes advantage of that environment
variable to force the installation of the latest Java update from Apple.