Modern web applications using React and other frameworks are often distributed as static websites. It is undoubtely the simplest, cache-friendly and dead-cheap solution. However, some enterprisey projects (think about data-entry and legacy business applications) need to be deployed in a constrained environment like a Java JEE Servlet Engine (Tomcat, Jetty, Resin) or a full-fledged Application Server (Weblogic, JBoss / WildFly, Websphere). Forget having your app deployed on a separate “lightweight” web server like Apache or Nginx, let alone a dedicated 3rd-level domain or IP address like frontend.
Update 2017-08-01 Updated “Behavior-Driven Development (BDD) and Test-Driven Development (TDD)” section, adding bddblock template I’m a IntelliJ IDEA user since late 2013. After a long (and not without problems) liaison with Eclipse IDE, and before that with the glorious Borland JBuilder, I wanted to try something new. Not that Eclipse was bad per se, it was just getting heavier and buggier release after release, and the plugin ecosystem wasn’t anymore something you could rely on.