Java Reference
In-Depth Information
Object-Oriented
Programming:
Polymorphism and Interfaces
10
General propositions do not
decide concrete cases.
—Oliver Wendell Holmes
A philosopher of imposing
stature doesn't think in a
vacuum. Even his most abstract
ideas are, to some extent,
conditioned by what is or is not
known in the time when he
lives.
—Alfred North Whitehead
Objectives
In this chapter you'll:
Learn the concept of
polymorphism.
■
Use overridden methods to
effect polymorphism.
■
Distinguish between abstract
and concrete classes.
■
Declare abstract methods to
create abstract classes.
■
Learn how polymorphism
makes systems extensible
and maintainable.
■
Determine an object's type at
execution time.
■
Declare and implement
interfaces, and become
familiar with the Java SE 8
interface enhancements.
■
