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.