Advising beans(Chapter 4 of Spring In Action)

　　Advice

　　In AOP terms, the job of an aspect is called advice.Advice defines both the what and the when of an aspect. In addition to describing the job that an aspect will perform, advice addresses the question of when to perform the job.

　　Joinpoint

　　A joinpoint is a point in the execution of the application where an aspect can be plugged in. This point could be a method being called, an exception being thrown, or even a field being modified. These are the points where your aspect’s code can be inserted into the normal flow of your application to add new behavior.

　　Pointcut

　　If advice defines the what and when of aspects then pointcuts define the where. A pointcut definition matches one or more joinpoints at which advice should be

woven. 

　　Aspect 

　　An aspect is the merger of advice and pointcuts. Taken together, advice and pointcuts define everything there is to know about an aspect—what it does and

where and when it does it.