Example:
public class Java1 { public static void main(String[] args) { System.out.println("java".toUpperCase()); System.out.println("java".toUpperCase()); } }
Note that the expression "java".toUpperCase() is evaluated twice. To avoid this, we could store the result of the evaluation of this expression in a variable and reuse it for printing.
public class Java2 { public static void main(String[] args) { String line; line = "java".toUpperCase(); System.out.println(line); System.out.println(line); } }
In the Java2 program, line is a variable of type String to which we assign the value of "java".toUpperCase(), which is then printed twice.
A variable represents a memory location that can be used to store the reference to an object.