In Spring Aspect-Oriented Programming (AOP), the term "concern" refers to a particular behavior or piece of functionality that you want to implement within a specific module of an application. It represents a functional area of interest that can be encapsulated in a module or component. For example, the operations performed by a banking application, such as transferring funds or checking balances, can be considered concerns because they represent distinct functionalities within the application[2].
On the other hand, a "cross-cutting concern" is a type of concern that is applicable throughout the application and affects multiple modules or components. These are aspects of a program that cannot be cleanly decomposed into the application's primary functional components because they affect multiple points of the application. Common examples of cross-cutting concerns include logging, transaction management, security, and performance monitoring. These concerns are termed "cross-cutting" because they "cut across" multiple points of an application, rather than belonging to a single, specific module[2][3][4].
