Final Keyword in Java Explained with Examples

 

Final Keyword in Java

The final keyword in Java is used to make a variable’s value constant, meaning the value cannot be changed once assigned.

Final Variables

When a variable is declared as final:

• The variable must be initialized once
• Reinitialization is not allowed
• Any attempt to change the value results in a compile-time error

Example:

final int x = 10;

// x = 20; // Compile-time error

Final with Static and Instance Variables

• When a static variable or instance variable is declared as final, it does not support default values
• Such variables must be declared and initialized together
• The value must be assigned only once

Valid syntax:

class Example {

    static final int A = 100;

    final int B = 50;

}

Purpose of Final Keyword
The final keyword is used to:

• Create constant values
• Prevent accidental modification of variables
• Improve code readability and safety