Programming in the Large II
Objects and Classes
WHEREAS A SUBROUTINE represents a single task,
an object can encapsulate both data (in the form of instance
variables) and a number of different tasks or "behaviors"
related to that data (in the form of instance methods).
Therefore objects provide another, more sophisticated
type of structure that can be used to help manage the complexity of
This chapter covers the creation and use of objects in Java. Section 4
covers the central ideas of object-oriented programming: inheritance and
polymorphism. However, in this textbook, we will generally use these ideas
in a limited form, by creating independent classes and building on existing classes rather than by
designing entire hierarchies of classes from scratch. Sections 5 and 6
cover some of the many details of object oriented programming in Java.
Although these details are used occasionally later in the book, you might want to skim
through them now and return to them later when they are actually needed.
Contents of Chapter 5: