Course Content

Java Extended

1. Deep Java Structure

How does the compiler works?Data transfer in Java Final Keyword Importing Libraries Using Libraries In Our Code Ternary Operator Enhanced Switch Statement

2. Methods

What is a Method?Creating Our Own Methods Challenge: Names Starting with Letter B Void Methods Practice Method Overloading Recursion Sorting Even Numbers Challenge

3. String Advanced

Deeper into String Method split()Uppercase Even Words Challenge indexOf() method Character Indices Sum Challenge trim() Method Substring First and Last Characters Challenge

4. Classes

What is class?Main Class and Method Access modifiers Class Creation Cat Meowing Challenge Constructor Team Constructor Challenge Method toString()Parrot Information Display Challenge

5. Classes Advanced

Complex Classes Usage Pet and Owner Relationship Challenge Private Modifier Animal Information Display Challenge Getter and Setter Country Information Management Challenge Summary

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.

Note
Just using the keyword final alone is not enough to create a constant. To create constants, the construct private static final is used. Additionally, all constants have uppercase names separated by underscores, for example:
private static final int NUMBER_OF_CHESS_PLAYERS = 2;

Task

Here is the code where I create multiple variables and perform mathematical operations on them. However, I only perform these operations on certain variables. Your task is to add the final keyword before the variables that I do not modify in this code to prevent me from accidentally changing them later.

Note
It is not necessary to use final everywhere. Use this keyword only when you are certain that you will not need to change the value of the variable in the future. If you use this keyword where it is not needed, you may confuse yourself in your own code.

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.

Note
Just using the keyword final alone is not enough to create a constant. To create constants, the construct private static final is used. Additionally, all constants have uppercase names separated by underscores, for example:
private static final int NUMBER_OF_CHESS_PLAYERS = 2;

Task

Note
It is not necessary to use final everywhere. Use this keyword only when you are certain that you will not need to change the value of the variable in the future. If you use this keyword where it is not needed, you may confuse yourself in your own code.

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.

Note
Just using the keyword final alone is not enough to create a constant. To create constants, the construct private static final is used. Additionally, all constants have uppercase names separated by underscores, for example:
private static final int NUMBER_OF_CHESS_PLAYERS = 2;

Task

Note
It is not necessary to use final everywhere. Use this keyword only when you are certain that you will not need to change the value of the variable in the future. If you use this keyword where it is not needed, you may confuse yourself in your own code.

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

Everything was clear?

Thanks for your feedback!

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.

Note
Just using the keyword final alone is not enough to create a constant. To create constants, the construct private static final is used. Additionally, all constants have uppercase names separated by underscores, for example:
private static final int NUMBER_OF_CHESS_PLAYERS = 2;

Task

Note
It is not necessary to use final everywhere. Use this keyword only when you are certain that you will not need to change the value of the variable in the future. If you use this keyword where it is not needed, you may confuse yourself in your own code.

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

Section 1. Chapter 3

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