Final Keyword

How to prevent changing the value of a variable

For this purpose, Java has a keyword called final. Let's consider a code snippet where we use this keyword:

Main


              123456789101112
            
package com.example;

public class Main {
    public static void main(String[] args) {
        int number = 10;
        final int finalNumber = 5;
        number = 15;
        finalNumber = 20;
        System.out.println(number);
        System.out.println(finalNumber);
    }
}

You can see that in the code above, we have created two variables of type int, but one of them is marked with the final keyword. When we try to change the value of this variable, the compiler tells us about an error. Specifically, it indicates that we cannot modify a value that is marked with the final keyword.

What can we use final keyword for:

To create constants. A constant is a variable whose value cannot be changed after it has been initialized. In Java, constants are always declared using the final keyword;
To indicate that the value of a variable is final and should not be modified;
To prevent accidental modification of a final variable's value in our code.

Task

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Your task is to add the final keyword before the variables that are not modified later in the code.

_{Once you've completed this task, click the button below the code to check your solution.}

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 3

Final Keyword

How to prevent changing the value of a variable

For this purpose, Java has a keyword called final. Let's consider a code snippet where we use this keyword:

Main


              123456789101112
            
package com.example;

public class Main {
    public static void main(String[] args) {
        int number = 10;
        final int finalNumber = 5;
        number = 15;
        finalNumber = 20;
        System.out.println(number);
        System.out.println(finalNumber);
    }
}

What can we use final keyword for:

To create constants. A constant is a variable whose value cannot be changed after it has been initialized. In Java, constants are always declared using the final keyword;
To indicate that the value of a variable is final and should not be modified;
To prevent accidental modification of a final variable's value in our code.

Task

Swipe to show code editor

Your task is to add the final keyword before the variables that are not modified later in the code.

_{Once you've completed this task, click the button below the code to check your solution.}

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 3

Switch to desktop for real-world practiceContinue from where you are using one of the options below