In the old days when we built applications, it was from the perspective of the specific problem they solved. An application might be built to enable a company to bill its customers and pass payment on to suppliers; an application would be created to capture credit information or to create a supply chain. In each of these instances, the application was built as a standalone entity contained within an architected application. In most cases today, this hasn't changed. What is starting to change is the nature of what an application is and how it works.
As businesses start to move away from this conventional programming model of creating self-contained applications, they start to build business components or services. This is an exciting trend that will ultimately offer a much higher level of predictability in the development process. Developers will use predefined business components that have been tested and contain the approved corporate policies. In order to make these business components usable, the developer knits them together with industry standard web services linking technologies. So far, this is simply an evolution of what we have been experiencing for decades. However, the similarities end here. We are about to embark on a new era where we have to think differently about the nature of an application. Many companies that are starting to plan for service oriented architectures haven't come to terms with the redefinition of the application.
This became apparent to me the other day when I had a meeting with the CIO of an insurance company. We had been talking about service oriented architectures and web services and new models of creating this predictable value. While he has already started helping his organization move in this direction, he was confused. What is the container? Into what do you put this set of linked business services? It isn't simply a piece of code, and it isn't a traditional application with a beginning, middle and an end; so, what is it? Does it simply float in space? And just as important, how will we manage this composite environment so that its performance is predictable? These are excellent questions and ones that I believe are being asked silently across our industry. It is not being articulated very often because no one wants to be the first to say that 'the emperor has no clothes', so to speak.
