Introduction

Real production environments still operate on many legacy applications that are written in a variety of programming languages. As the adaptation of the applications for integration presents a big work effort and costs a lot of money, a better approach is to expose the application functionality through API and web services. Other mechanisms for integration are also mentioned in this book, such as REST, JMS, EJB, and so on. This way, however, it is easier to integrate other applications with legacy application, as we can integrate different applications in a technology-neutral manner. Also, we can take advantage of other web service features such as interoperability and reusability.

As this book addresses Java and BPEL, we cover the aspects of how to expose the already existing Java code as a web service. To some extent, we already covered this in Chapter 8, Exposing Java Code as a SOAP Service. We start by defining the service interface which presents the entry point for other...