Aspect

An internet company knows which customer has what internet plan. On the basis of this information the internet company calculates an internet bill and sends it to the customer. In this example internet company is an aspect, internet plans are pointcuts and customers are join points, and calculating internet bills by the company is an advice. Likewise, in your application, an aspect is a module that encapsulates pointcuts and advice. Aspects know what it does; where and when it does it in the application. Let's see how AOP applies the aspect to the business methods.