Can you briefly describe about local interfaces? (EJB)

Question :Can you briefly describe about local interfaces? (EJB)
Answer :EJB was originally designed around remote invocation using the Java
Remote Method Invocation (RMI) mechanism, and later extended to
support to standard CORBA transport for these calls using RMI/IIOP. This
design allowed for maximum flexibility in developing applications without
consideration for the deployment scenario, and was a strong feature in
support of a goal of component reuse in J2EE.
Many developers are using EJBs locally -- that is, some or all of their EJB
calls are between beans in a single container.
With this feedback in mind, the EJB 2.0 expert group has created a local
interface mechanism. The local interface may be defined for a bean during
development, to allow streamlined calls to the bean if a caller is in the
same container. This does not involve the overhead involved with RMI like
marshalling etc. This facility will thus improve the performance of
applications in which co-location is planned.
Local interfaces also provide the foundation for container-managed
relationships among entity beans with container-managed persistence.