Design patterns·Objects, messages and the principles
you got twenty methods you never asked for along with the one you wanted, and you cannot give any of them back.
Inheritance
Also calledsubclassing, class inheritance, extends
Deriving a class from another so it acquires the parent's fields and methods and may replace some of them. It is the strongest coupling one class can have to another: the subclass depends not just on the parent's public surface but on which of its own methods the parent calls internally. That is why it is the default in textbooks and increasingly the second choice in practice.