Java EE -- is it just fluff or the real stuff?

Question

I'm familiar with the LAMP stack and over the years have successfully deployed a handful of web sties based on it. I've used everything from Apache + modPerl, to PHP, to Ruby and Rails. With good use of caching my Rails site can sustain a pretty good load, but I'm not talking massive.

I never really liked Java as a language, or XML for that matter, and have very much been ignoring the whole Java EE side of things. For those who have had real and direct experience in both worlds: is there something super cool about Java EE that I'm missing, or is just a bunch of hot air? What justifies the high price of the proprietary app servers?

I'm not trolling here: I'm looking for concrete examples of things that Java EE really nails that are missing from modern LAMP frameworks, if such differences exist. (Modern = Rails, Django, etc). Alternatively pipe in with those things that LAMP really does better (fewer XML sit ups for one).

+++++ Update October 16, 2008

I'm sad to report that most of the replies here are not helpful, and simply fall into one of two categories: "It scales because here are three examples of large web sites" and "It scales because it is really actually much better than the LAMP stack".

I've done quite a bit of reading, and have concluded that Java EE only has one really good trick: transactions (thanks Will) and as for the rest you can succeed or fail on your own merit, there is nothing intrinsically in the environment to cause you to create a scalable and reliable web site, indeed Java EE has quite a few traps that make it easy to fail (for instance it is easy to start using session beans without realizing that you are paying now for quite a bit of JMS traffic that perhaps could have been avoided with a different design.)

Useful discussion

• http://www.subbu.org/blog/2007/10/large-scale-web-site-development
• http://highscalability.com/
• http://www.oreillynet.com/onlamp/blog/2004/07/php_scales.html
• http://www.schlossnagle.org/~george/blog/index.php?/archives/29-Why-PHP-Scales-A-Cranky,-Snarky-Answer.html
• http://blogs.law.harvard.edu/philg/2003/09/20/

Answer 1

The key differentiator that Java EE offers over the LAMP stack can be boiled down to a single word. Transactions.

Most smaller systems simply rely on the transaction system supplied by the database, and for many applications that is (obviously) quite satisfactory.

But each Java EE server includes a distributed transaction manager. This lets you do more complicated things, across diverse systems, safely and reliably.

The most simple example of this is the simple scenario of taking a record from a database, putting it on a messaging queue (JMS), and then deleting that row from the database. This simple case involves two separate systems, and can not reliably be done out side of a transaction. For example, you can put the row on to the message queue, but (due to a system failure) not remove the row from the database. You can see how having a transaction with the JMS provider and a separate transaction with the database doesn't really solve the problem, as the transactions are not linked together.

Obviously this simple scenario can be worked around, a dealt with, etc. The nice thing with Java EE, though, is that you don't have to deal with these kind of issues -- the container gets to deal with them.

And, again, not every problem requires this level o transaction handling. But for those that do, it's invaluable. And once you get used to using them, you'll find the transaction management of a Java EE server to be a great asset.