Identifiers
An identifier is a word that you make up to associate a name with a Java programming element, such as a variable, field, parameter, class, or method.
Here are the rules for creating identifiers:
Identifiers are case-sensitive. As a result, SalesTax
and salesTax
are distinct identifiers.
Identifiers can be made up of uppercase or lowercase letters, numerals, underscore characters (_
), and dollar signs ($
). Thus, you can have identifier names such as Port1
, SalesTax$
, and Total_Sales
.
All identifiers must begin with a letter. Thus, a15
is a valid identifier, but 13Unlucky
isn’t (because it begins with a numeral).
An identifier can’t be the same as any of the Java keywords listed earlier in this part. Thus, you can’t create a variable named for
or a class named public
.