Confused. Why does the first sentence of the first paragraph refer to there being three objects, when there are only two that I can see. The first is an interface BookDao which by definition isn't an object, not an instance of the interface. Shouldn't it be two objects and one interface?
posted 3 months ago
I believe the third object they left out was class Student referred to on page 557? Then it would be one interface and three objects, a) Student, b) InMemoryBookDao. and c) Book.