A variable is a container that holds values that are used in a Java program. Every variable must be declared to use a data type. For example, a variable could be declared to use one of the eight primitive data types: byte, short, int, long, float, double, char or boolean. And, every variable must be given an initial value before it can be used.


int myAge = 21;

The variable "myAge" is declared to be an int data type and initialized to a value of 21.