I have a Spring Boot project using Jersey as my REST service and using AngularJS for my front end development. While I run it without using any controller and go to index.ht
This is because you annotated your controller with @RestController, which is a shorthand for @Controller with @ResponseBody. The latter annotation instructs the controller to render the output as-is directly into the response.
Use @Controller for controllers that are not RESTful instead.