It should be noted that you are now referring to the sanest part of Java Server Faces, i.e. its first template system: Java Server Pages or JSP. If think JSP that compiles to a bunch of Servlets filled with print statements is bad, you really have to look at the rest of that stuff; because it gets a lot worse :-)

The stateful design, which fills up templates with a bunch of hidden html-input fields, in order to open web-pages in the same "state" as you left them and all sorts of other crap.

You also need to look into Portlets, which "splits" up a web-pages into seemingly stand-alone components. These are then combined into horribly complicated Servlets as you deploy, where http paramters are namespaced with some random _portletId=lsøjfksjo1920 things in order to figure out which parameters goes to which "part of the web-page". Again, all of this is so bad, you'd think it was a joke; but it was Java's offering for web-development, and a huge number of people CHOOSE that technology in the early 2000's.