Validating and Using the Model Data - Oracle ADF 11gR2 Development Beginner's Guide - page 118

3. The Edit Client Interface window will open. Move the getHelloWorld() method
from the Available list to the Selected list as shown in the following screenshot:
4. Click on the OK buton to create the interface method.
What just happened?
We now have the client interface defined to expose the getHelloWorld() method from
the EmpDirectoryModuleImpl class to the outside world. The EmpDirectoryModule.
java interface will be created to expose the method as a service in the data control.
The EmpDirectoryModuleClient class will implement the interface to invoke the
getHelloWorld() method from EmpDirectoryModuleImpl .