From DeveloperWorks, WebSphere Process Server invocation styles
As you author applications in WebSphere Integration Developer, you may find it necessary to set or verify the invocation style that one component will use to call another. Users are often surprised to find that this is not as easy a task as it may seem. This article explains how to determine which invocation style will be used at runtime, based on characteristics of your application.
Another article from my former colleagues (they’re been busy!). This one explains what interaction style an invocation will use between two component. This is important to understand for error handling and transaction boundary issues. Another must read.