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Constant Variable in Java Programming

Java Basic Concepts

In this lesson, we will look at what is constant variable and how to declare one with the help of some example. We will also play a quiz at the end.

What is Constant Variable

A Constant variable in Java is a variable whose value does not change during the execution of the program. Once a value is assigned, in a constant variable, it remains fixed throughout the program. A Constant variable is declared by keyword final.


Syntax of Declaring Constant Variable in Java

final datatype variable_name;

Here final keyword is used for declaring Constant, datatype is the name of data type such as int, float, double or char and variable_name is the name of variable (you can use any name of your choice for example: a, b, c, alpha, etc.) and ; is used for line terminator (end of line).

Now let's see the example for more understanding.


Declare constant variables of each datatype.

final int a = 23;  		    // a becomes integer constant variable
final float b = 56.36f;  	// b becomes float constant variable
final double c = 75.3215;  	// c becomes double constant variable
final char d = 'k';  		// d becomes character constant variable

Note: Now the above-declared variables are constant, it means that their values can't be changed during execution of the program.

Test Your Knowledge

Attempt the multiple choice quiz to check if the lesson is adequately clear to you.

Test Your Knowledge