Frontends of most modern applications are not built using server-side web application frameworks, such as Spring MVC, Java Server Faces (JSF), and so on. Infact, many are built using full-fledged client-side frameworks, such as React (to be full-fledged, it has to be combined with other libraries), Angular, and so on. The previous statement doesn't mean in any way that there is no place for such server-side web application frameworks. According to the application you are building, there are specific places for each of these frameworks.
When using client-side frameworks, the client code (HTML, JS, CSS, and so on) in general is not secured. However, the data required to render these dynamic pages is secured behind a RESTful endpoint.
To secure a RESTful backend, the JWT is used to exchange claims between the server and the client. The JWT enables...