How large is the gap though? If an experienced Java dev wants to build a website/application should they learn a new language or possibly have a single page app with a Java-backed REST service? Or should they pick one of the many frameworks, like GWT, Vaadin, JSF, PrimeFaces, or one of many MVC frameworks? After exploring both single page application frameworks and Java frameworks, there seems to be quite a large learning curve, one that there isn’t time for. Why can’t we build a very quick server side rendered website for a quick MVP or even a full-size project?