How to explain an object?

Question

It\'s been years since I thought of this, but I am training some real juniors soon and need to explain what an object is to someone who doesn\'t know what it is.

B

Answer 1

My experience as a self-learner is that I introduced a fair amount of trouble in my head with the concept of object as mapped to a "real entity" like animals and cars and so on. It forms your head in willing to find a realistic (as in "the real world") taxonomy in your business objects even when there's none, and it confuses you in finding unrealistic taxonomical classification that are instead useful for real OO design (eg. design patterns). Finally, it pushes you to the point that you fossilize in one "real world" taxonomy even if other "less real world" can exist and they are better.

In any OOP book you find that a square is a kind of rectangle, and so a square is represented as inherited by a rectangle, but we know that this approach is deeply flawed (I read a paper on that, don't remember where, but you can search about the "fragile base class problem" in google). Also, in some programming languages, you don't need OO taxonomy for interface inheritance (see my post on this regard).

So, my suggestion is: present it but be very careful how far you go, and eventually switch immediately from the "car and animals" examples to a less nice to present taxonomy. You can deeply flaw their understanding if you push it too far.