Enterprise applications have some common cross-cutting concerns that are applicable to different types of Objects and application modules, such as logging, transaction management, data validation, authentication etc. In Object Oriented Programming, modularity of application is achieved by Classes whereas in AOP application modularity is achieved by Aspects and they are configured to cut across different classes methods.
AOP takes out the direct dependency of cross-cutting tasks from classes that are not possible in normal object-oriented programming. For example, we can have a separate class for logging but again the classes will have to call these methods for logging the data. Read more about Spring AOP support at Spring AOP Example.