Are AS (with EJBs) the only way for JEE client/server communication?

Question

Imagine a Java client/server ERP application serving up to 100 concurrent users, both web and swing clients. For persistence we can use Persistence API and Hibernate. But when it comes to client/server communication, do we really have an alternative to using an AS with EJBs to keep down the programming costs of remote communication?

It seems a very heavyweight solution to throw in EJBs and an application server, just for remoting stuff. There is also the standard way using RMI, but who wants nowadays to code everything on his own...

I know that you'll get a lot of features for free with an AS in addition to the remoting part. And, maybe it's the way to go. But, are there really any other (low programming cost) alternatives to an AS for doing client/server communication for an enterprise application?

Answer 1

You can use light weight remoting frameworks. Spring is having a number of options in this section.

If you ask me one word for both, I will suggest two. Seam or Spring. I myself like Seam, but for lightweight remoting Spring has more viable solutions and support. Again if your AS is JBoss, give a thought to Seam.

Answer 2

An application server is a pretty heavyweight solution. Depending on your requirements, I would try to make sure that you can run on a simple servlet container (like Tomcat). I find remoting much easier with Spring-remoting instead of full EJB. Spring-remoting provides an abstraction on the actual remoting technique used. Hessian has a good reputation as a lightweigth protocol.

Having some sort of a server framework (AS or servlet container) is a good thing as you wont need to think as much about all the low level problems (connection establishment, threading, ...).

Answer 3

Personally I consider Seam to be the ultimate solution to the problem I don't have but that aside, there are lots of options and Spring is used for most of them:

• RMI;
• Hessian (binary HTTP based protocol);
• HTTP Invokers (Java serialization over HTTP);
• Web Services; or
• Even JMS.

The advantage of the HTTP based remoting methods is that they easily plug into Spring's security models. Plus then you get access to things like interceptors.