It's reasonable to provide a single implementation of an interface, if the goal is to facilitate dependency injection for that component. The problem I find wit

It's reasonable to provide a single implementation of an interface, if the goal is to facilitate dependency injection for that component. The problem I find with Spring is that it is designed for dependency injection at all levels of its architecture, leading it to be one of the ultimate examples of Ravioli Code. https://wiki.c2.com/?RavioliCode https://wiki.c2.com/?RavioliCode DI is a powerful concept, but Spring projects rely on DI in such a generic way that it often doesn't even make sense for your application. You have to gain intimate knowledge of the abstractions, and inject a bunch of code in a bunch of places just to make it do the very-straightforward thing you were trying to do.