OO concepts live on whenever we are talking about interfaces, contracts and the like. The failed experiment is "true" object oriented domain modeling, the idea

OO concepts live on whenever we are talking about interfaces, contracts and the like. The failed experiment is "true" object oriented domain modeling, the idea that software representations of real entities (an order, a dog, a car) should include code beyond maybe some basic constraint checking. Other than that, thehe OO tools are still powerful and some form of encapsulation is essential for any data structure that is more complicated than a pain array or a one-way linked list. But these structures are not representations of real objects, they are actual data objects. A hashmap isn't a representation of a hashmap, it is the real thing (even if it maps representations of dogs to representations of cars).