Since no one has answered yet, I'll give it a go.
You DO need Java on the server. I am uncertain if the JRE is enough, or if you need the full Java "SDK" or Java Enterprise package. (Both are downloadable)
On the client side, you should to the best of my knowledge NOT need any form of java installed, UNLESS you want to use the old/deprecated Java applets for printing etc (DON'T! Use the HTML5 versions instead!!!).
I hope and believe that this is fully correct and helps you out.