The basic concept is that the IoC container can override abstract or concrete methods on managed objects on deployment. The container is injecting a method, such as a getter method, rather than a reference or primitive as in Setter Injection. As it happened, I was already working on a container method override mechanism for Spring 1.1, which has since been released in Spring 1.1 RC1. It’s an interesting concept, and definitely part of a complete IoC container. However, I believe that the concept is more general and needs a more general name. Also, that it should only be used in a fairly narrow range of scenarios.