A. it provides centralized request handling for incoming requests.
B. It forces resource authentication to be distributed across web components.
C. It reduces coupling between presentation-tier clients and underlying business services.
D. It can be added and removed unobtrusively， without requiring changes to existing  code.
E. It allows preprocessing and postprocessing on the incoming requests and outgoing  responses.

A. The method invoked by this function must be statie.
B. The function class must implement the Function interface.
C. The expression is NOT a valid EL expression for invoking a function.
D. The function must be declared in a web.xml file using the  element.
E. The function class must have a method with the signature：Void bloof （java.lang.Strings）