AOP Alliance is an open-source project that defines a set of standard interfaces for AOP implementations. The goal of the project is to make it easier to write AOP-based applications, and to promote interoperability between different AOP implementations. The AOP Alliance interfaces are designed to be generic and applicable to a wide range of programming environments. The project includes interfaces for pointcuts, advisors, and bindings. In addition, the project defines a set of AspectJ-style join point signatures that can be used with any AOP implementation.