Using Objects - Java Concepts - page 45

In Java, every value has a type.

You often want to store values so that you can use them at a later time. To remember
an object, you need to hold it in a variable. A variable is a storage location in the
computer's memory that has a type, a name, and a contents. For example, here we
declare three variables:

String greeting = "Hello, World!";
PrintStream printer = System.out;
int luckyNumber = 13;

The first variable is called greeting . It can be used to store String values, and it
is set to the value ÐHello, World!Ñ . The second variable stores a PrintStream
value, and the third stores an integer.

You use variables to store values that you want to use at a later time.

Variables can be used in place of the objects that they store:

printer.println(greeting); // Same as System.out.println("Hello,
World!")
printer.println(luckyNumber); // Same as System.out.println(13)

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S YNTAX 2.1 Variable Definition

typeName variableNameÉ=Évalue;

or

typeName variableName;

Example:

String greeting = ÐHello, Dave!Ñ;

Purpose:

To define a new variable of a particular type and optionally supply an initial value

When you declare your own variables, you need to make two decisions.