Notice: This page requires JavaScript to function properly.
Please enable JavaScript in your browser settings or update your browser.Lära Final Keyword | Deep Java Structure
Java Extended

Svep för att visa menyn

book
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:

java

Main

copy

              
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.

Uppgift

Swipe to start coding

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

Lösning

java

solution

Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 1. Kapitel 3

Fråga AI

expand
ChatGPT

Fråga vad du vill eller prova någon av de föreslagna frågorna för att starta vårt samtal

book
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:

java

Main

copy

              
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.

Uppgift

Swipe to start coding

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

Lösning

java

solution

Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 1. Kapitel 3
Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Vi beklagar att något gick fel. Vad hände?
some-alt