The question how to deal with existing systems often seems easy to answer – at least in high level analyst presentations and glossy vendor brochures: just build a wrapper and make it look like a service. This way the legacy system can become an equal citizen in the world of SOA.

Of course, the reality that we face in our client projects is usually quite different. Keeping a “wrapped” legacy system alive does not end the maintenance burden that it has become over the years. And building the service wrapper is often not possible in a non-intrusive way, which can result in a price point that makes the approach not feasible; this approach can also have severe side effects that create a risk that is not acceptable.

Successful SOA Integration requires a careful approach that weighs the benefits of the available options against their cost and risks.