Eye Grabbers   

I was reading on SOA just in the recent past and couldn't resist the temptation of asking myself what or who
to challenge it now.Theres a no rest battle right now.There is a passionate debate raging on the merits of SOA versus REST that I don't get. Some argue that SOA/WS-* is too complex and too "enterprisey" and that we should write off the complex WS-* standards approach in favor of a simpler REST approach.

There is also the need to aggregate fine grained services into business processes. This concept is supported with model driven tools that orchestrate a set of services to form a more complex business process. Weblogic provides a clean abstraction to invoke EJB layer specifically Stateless Session Bean through JAX-RPC style with effortless ease.
To put URIs around a set of services that will never be presented in a browser to be aggregated for reuse doesn't make much sense. Even if web services did not exist, I would not use REST for this purpose. I would use messaging such as JMS.

Messaging brings up another issue with REST inside the firewall. It is often desirable to use SOAP over JMS versus HTTP inside the firewall to simplify transaction management and security. For example, you could expose a web service as HTTP(s) externally and though a gateway service as SOAP over JMS internally. Protocol abstraction, security and transaction management are more enterprisey details you have to bake into your SOA.

Development tools support importing WSDLs, generating WSDLs, creating SOAP request documents for debugging and so on. Some of the more complex WS-* standards are now supported in tools, with many more to follow, that abstract this complexity from the developer such as DataPower's support for SAML and federated identity management. The concept of federated security is indeed enterprisey, but for many a necessity.

I have nothing against REST. In the early days of the Internet we had built several e-commerce systems with these techniques - back then, I did not even know I was using REST when building those long, ugly URIs. But the tools being created now for developer's use are moving to WS-* standards support to solve enterprise class problems. I personally think enterprise wide and complex problems are most interesting but though iam not a expert on SOA implementations or systems.