Java Reference
In-Depth Information
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Objects and Classes
In This Chapter
The COBOL Subroutine
Calling a Subroutine
Terms to Review: Subroutines
Objects and Java
Terms to Review: Objects
Java's popularity is due to a number of factors. One of the biggest reasons is that it
is a popular object-oriented language.
This sounds impressive, but what exactly is an object-oriented language? In
fact, what is an object?
Simply put, an
object
is a collection of code organized to perform a function or
simply to retain some information on behalf of another program. Objects are cre-
ated and then used by programs to perform these functions on behalf of the other
programs.
Object-oriented (OO) languages, and the object-oriented design approach,
contain many ideas already familiar to you. Chapters 1 through 5 will start by de-
scribing these concepts, based on the COBOL language. I will then compare Java's
definition of objects, and the syntax that supports it, to these concepts. This should
help you acquire a good understanding of the basic object-oriented concepts.
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