I don't know about you but my experience with Java required me to type either the same or less than JS if we are comparing apple vs apple, not simple front end vs complicated back end.
Are you counting Java IDE keystrokes or actual number of characters on the screen? If it's the latter, I'd be interested in seeing an example since it's very much against the wisdom of the crowds here.
My experience is that the complicated part web app is the part that does the state coordination, which can be either end.
My experience is that the complicated part web app is the part that does the state coordination, which can be either end.