[ptrwis]

I don't know, but maybe these application servers are certified in some way so that they can be used in the right places that require certification (I'm guessing, not sarcastic)? Which would make sense, but some people host applications written in Spring on JavaEE application servers, which is like adding ketchup to a Greek salad. For me, Java EE standardization makes absolutely no sense. You code to common programming interfaces when you need to break them down to use the underlying implementations. Now I code in .Net and at least I don't have such dilemmas.