I think the GP is referring to the use of interfaces with only one implementing class, rather than interfaces with no implementing class. i.e. you end up creati

I think the GP is referring to the use of interfaces with only one implementing class, rather than interfaces with no implementing class. i.e. you end up creating a UserProvider and UserProviderImpl for every service class you write. OP is probably referring to the JDK Proxy support which is used by Spring and requires classes to implement at least one interface.