20 years ago. We had enterprise java, it’s still “there”, but running spring is very different from what it used to be.

You’d simply upload an ear or ear and the server and deployed would handle configuration like db etc.

It worked perfectly (ear/war, the persistence framework was too verbose and high level imo, but that was replaced by hibernate/jpa). There was too much configuration in xml, but that could easily be replaced my convention, annotations and some config

Again.. we are running in circles, and this industry will never learn, because most “senior” people haven’t been around long enough.