I added this platform for sake of completeness, but I have no love for it at all. Part of the problem is that Red Hat wants to make money in its usual, inimitable way: charge for the version that is actually usable. Out of the box the community edition of JBoss is lacking compared to all of its competition. (No administration console for starters.) Sadly it was one of the earliest open source application servers so it has the market share.

I suspect much of the loathing people have for writing Java EE applications stems from the fact that JBoss was the dominant platform for doing it.