IntroductionMethodInterceptor spring AOP

I was reading folowing lines and I did not understand clearly.

This method is critical to how introduction works. implementsInterface returns
true if the IntroductionMethodInterceptor is responsible for implementing the
given interface. This means that any invocation of a method that is declared by
this interface will be delegated to the invoke() method of the Introduction-
MethodInterceptor. The invoke() method is now responsible for implementing
this method—it cannot call MethodInvocation.proceed(). It is introducing the
new interface; proceeding to the target object doesn’t make sense.


Any ideas, resources,sample code,links, highly appreciated. thanks in advance.