How to open my Jar file without JDK?

So I have a school computer, this one is just a substitute my school gave me because my other one is getting fixed. I put my techniclauncher.jar file in a USB so I can transfer it on the loner and play minecraft. Well now its on the loner but it says this when I try to open it.
"To use the "Java -jar TechnicLauncher.jar" command line tool you need to install a JDK" this thing is, I can't download the JDK because I have a school computer and I can't download anything on a school computer. How do I get this jar file to open with a JDK?

Added (1). I have a folder that apparently is a java folder called "jre-x64" what can I do with this? I got this folder from my windows computer that my brother use to get the techniclauncher over to my mac.

You don't need the JDK (Java development kit) to merely run java programs, but you will need the JRE (java runtime engine) to do so.

If you can't install anything and the computer doesn't already have Java installed, you're out of luck I'm afraid.