In this chapter we've seen how to implement crosscutting functionalities, such as concurrency control, the employment of a cache, and security management. Without AOP those functionalities would be scattered across the application, with the same code duplicated in different modules. With AOP we can have cleaner code, much more concise and easier to maintain and debug. We've seen how it is possible to implement these functionalities without having tangled or scattered code, implementing functionalities with aspects and advices.
Other important functionalities are transactions management, application logging, exception management, layout, and others. They will be illustrated in the next two chapters in a complete and working application.