Aspect Oriented Programming - AOP

Aspect-oriented software development is a new technology for separation
of concerns (SOC) in software development. The techniques of AOSD make
it possible to *modularize lightweight crosscutting* aspects of a system.

Allowing the business code focus on core business, polymorphism can make the business code with structure, but the public method across the discrete object cannot be code with polymorphism, AOP code can cover the area of public method

And reinformce seperation of concerns.

For example like Logging at a method level, it is difficult and cumbersome to inherit a base class for logging. it is hard to understand and difficult to maintain.

Security, caching and error handling, those are infrastructual coding related not business functionalities.