This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Service endpoint interface is an optional interface describing the operations that are to be exposed by the web service.
Service endpoint implementation class contains, as the name indicates, implementation of the service endpoint. It may contain additional methods that are not listed in the service endpoint interface.
Again, note that the service endpoint interface is not required. You can annotate methods in the service endpoint implementation class in order to expose, or prevent them from being exposed, as web service operations.