Java Identifiers

Identifiers

All Java variables must be identified with unique names.

These unique names are called identifiers.

Identifiers can be short names (like x and y) or more descriptive names (age, sum, totalVolume).

Note: It is recommended to use descriptive names in order to create understandable and maintainable code:

// Good
int minutesPerHour = 60;
 
// OK, but not so easy to understand what m actually is
int m = 60;

Rules for Naming Variables

• Names can contain letters, digits, underscores, and dollar signs.
• Names must begin with a letter.
• Names should start with a lowercase letter and cannot contain whitespace.
• Names can also begin with $ and _.
• Names are case-sensitive (myVar and myvar are different variables).
• Reserved words (like Java keywords, such as int or boolean) cannot be used as names.