Separate frontend and backend in Java - Spring MVC Framework

I'm new at Spring MVC framework i want to learn how to fully separate frontend(html,js etc.) and backend(java).

I'm going to use RESTfull services, play with JSONs. I think i'm going to build Single Page Application.

Most of tutorials shown in jsp pages which i dont like.

I saw my friends company project(Using Spring MVC) they used Embedded Jetty server and in server configuration they assigned two different paths for frontend and backend paths.

I saw frontend codes there was only html javascripts etc. on the backend side the approach was the same.(Fully Separated !!!)

My question is:'How they pass requests from frontend to backend and get results from backend and update frontend'.

Also they were using Maven backend and frontend defined as modules in the root.

Could you share tutorials so i can understand playing with codes ?