In this chapter, we learned how to invoke services and orchestrate services. We explained the primary mission of BPEL—service orchestration. It follows the concept of programming-in-the-large. We have developed a BPEL process that has invoked two services and orchestrated them. We have become familiar with the <invoke> activity and understood the service invocation's background, particularly partner links and partner link types.

We also learned that from BPEL, it is very easy to invoke services in parallel. To achieve this, we use the <flow> activity. Within <flow>, we cannot only nest several <invoke> activities but also other BPEL activities.

Now, we are ready to learn about variables and data manipulation, which we will do in the next chapter.