Aspect-oriented software development (AOSD, another name for AOP) enables developers to create common code once, and then to apply that code across an application dynamically, when and where needed. You create a construct called an aspect and then you define behavior as advice which specifies how and when to apply the aspect. The AspectJ runtime weaves the aspect code into the application, following the advice you specify.
This article shows portlet developers how to take advantage of AOP in portlets they implement to the Java Portlet Specification (JSR 168). It describes and provides examples in a download which implement crosscutting portlet functionality. The combination of JSR 168, AOP, and AspectJ technologies provides powerful and flexibility capabilities to portlet developers.