korell: I would imagine it works by having its own JRE folder within the game folder, rather than installing a system global JRE. That way the files are removed on uninstalling the game and they don't get referenced via system path parameters so it applies just to the game itself. Could do with confirmation on this, though.
EDIT: Yes, just looked at gamesfreak64's sw_jre.jpg image and it shows JRE within the game folder, so not a system global installation.
Martek: Yeah, I saw that folder in
gamesfreak64's post attachment. But that doesn't preclude that it also installs or requires that you have Java installed individually (especially since the 'official' Java site lists older versions of the individual install as
JRE's; and presumably this older game uses an older version of a JRE).
So knowing that the install creates a 'jre' subdirectory under the game doesn't rule out that the game also requires a separate Java install. That's the thing I'm wanting to find out.
I've had this game since god knows when, and it only uses its own (local) version of the JRE. Which it installs in its own directory only, and does not install in any system area whatsoever.
So no, it doesn't require an additional Java installation, nor does it use any other Java installation on your machine. It only uses the JRE it comes with to run the game.
It's not much different to how many games these days use Unity, and each game runs its own local version of the Unity engine as opposed to one system-wide one. (Although Unity in turn uses .NET (technically mono) and that does require system-wide installation of some libraries if I'm not mistaken).
Since the JRE this game uses is pretty ancient, I reckon it would have some issues if it attempted to run on any of the recent versions of the JRE (Java has changed since then - it's broken backwards compatibility a few times since that JRE).
As for security holes - since Java programs require the "Java Virtual Machine" (JVM), it's pretty obvious when a Java program is running since the JVM will be running - and it's easy enough to ensure you only run that when you need to (not letting any browsers/networks access it should do it). It's a hell of a lot easier to control and lock down than something that runs on the OS directly.