It is Design pattern
Problem:too many method invocations b/w client and server 
will lead to network overhead,tight coupling due to 
dependencies between the client and server and chance of 
misuce of server business methods due to fine grained 
access etc.
Solution: Use of session besn as facade to encapsulate the 
complexties b/w the client and  server interactions. The 
session facade manages the business objects and provides a 
uniform coarse grained service access layer to client.