A local interface or class instance must be in the same EJB container as the
bean whose interface it is. In contrast, a remote interface or class may be in
the same container or in another container on the same server or on a different server
as part of a distributed application. Accessing a local interface can be done with less
overhead and without involving the APIs for remote access. Accessing a remote
interface involves the full generality of the APIs that can do remote access.