When creating a SOA composite application, you have a choice of approaches for building it:

• Top-Down: You analyze your business processes and identify activities in support of your process. When creating a composite, you define all the SOA components through the SOA Composite Editor. You create all the services first, and then build the BPEL process, referencing the created services.

• Bottom-Up: You analyze existing applications and assets to identify those that can be used as services. As you create a BPEL process, you build the services on an as-needed basis. This approach works well when IT must react to a change.