It is called no interface view
if you let you Bean implement only one Interface you do not need to annotate the Interface or Bean, because the Container will use this Interface as LocalInterface by default.
The client who wants to use the EJBs Methods only see the public methods provided by the interface and all the other aspects of method implementation are hidden from the client.
So you can annotate bean or interface with @Local but you do not need it, if you only use one Interface.