Spring AOP with example

What is AOP ?

"AOP(Aspect Oriented Programming)  is programming way, that helps to increase modularity and avoids strong coupling of code by separating cross-cutting concerns". It is one of the key components of Spring Framework.

Cross-cutting concern is a code logic which is scattered throughout the application and it affects entire application. Transaction management and logging are best examples of cross cutting concerns. 

"The key unit of modularity in OOP is class, whereas aspect is the unit of modularity in AOP "

Spring IoC Container with XML configuration

What is IoC Container ? 

The org.springframework.context.ApplicationContext interface represents the Spring IoC container. This container instantiates, configures, and assemble beans by using externally provided configuration metadata.

ApplicationContext and BeanFactory are the same, but the ApplicationContext adds more enterprise-related functionality. In short, the ApplicationContext is a superset of the BeanFactory.