Cross-cutting concerns are applicable to all application layers--logging and security, among others. AOP is typically used to implement cross-cutting concerns.
Unit tests and integration tests fit this category since they are applicable to all layers.
Important Spring modules related to cross-cutting concerns are listed as follows:
| Module/Artifact | Use |
| spring-aop | Provides basic support for Aspect-Oriented Programming--with method interceptors and pointcuts. |
| spring-aspects | Provides integration with the most popular and fully featured AOP framework, AspectJ. |
| spring-instrument | Provides basic instrumentation support. |
| spring-test | Provides basic support for unit testing and integration testing. |
