1: Introduction to objects

Why has object-oriented programming had such a sweeping impact on the
software development community?
Object-oriented programming appeals at multiple levels. For managers, it promises faster
and cheaper development and maintenance. For analysts and designers, the modeling process
becomes simpler and produces a clear, manageable design. For programmers, the elegance
and clarity of the object model and the power of object-oriented tools and libraries makes
programming a much more pleasant task, and programmers experience an increase in
productivity. Everybody wins, it would seem.
If there’s a downside, it is the expense of the learning curve. Thinking in objects is a dramatic
departure from thinking procedurally, and the process of designing objects is much more
challenging than procedural design, especially if you’re trying to create reusable objects. In
the past, a novice practitioner of object-oriented programming was faced with a choice
between two daunting tasks:
1. Choose a language such as Smalltalk in which you had to learn a large library before
becoming productive.
2. Choose C++ with virtually no libraries at all,1 and struggle through the depths of the
language in order to write your own libraries of objects.
1 Fortunately, this has change significantly with the advent of third-party libraries and the Standard
C++ library.
42 Thinking in Java www.BruceEckel.com
It is, in fact, difficult to design objects well – for that matter, it’s hard to design anything
well. But the intent is that a relatively few experts design the best objects for others to
consume. Successful OOP languages incorporate not just language syntax and a compiler,
but an entire development environment including a significant library of well-designed, easy
to use objects. Thus, the primary job of most programmers is to use existing objects to solve
their application problems. The goal of this chapter is to show you what object-oriented
programming is and how simple it can be.
This chapter will introduce many of the ideas of Java and object-oriented programming on a
conceptual level, but keep in mind that you’re not expected to be able to write full-fledged
Java programs after reading this chapter. All the detailed descriptions and examples will
follow throughout the course of this book.