Of the abstraction. The values for getRadius() or getCircumference() in the above case in point can be stored straight, or they might be calculated, it does not issue into the caller; the setters may or might not have Uncomfortable side effects; it doesn't subject towards the caller. 3 It really https://www.diigo.com/item/note/b3f1u/vg5d?k=ae18f0ff71927e99362edb2a52a7323a