Java program to create an immutable class

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In this example, we will learn how to create an immutable class in Java.

To understand this example, you should understand the followingJava programmingTopic:

• Java Classes and Objects

Example: Java program to create an immutable class

final class Immutable {
　　private String name;
　　private int date;
　　Immutable(String name, int date) {
　　　　//Initialize immutable variables
　　　　this.name = name;
　　　　this.date = date;
　　}
　　//private getter method
　　public String getName() {
　　　　return name;
　　}
　　public int getDate() {
　　　　return date;}
　　}
}
class Main {
　　public static void main(String[] args) {
　　　　//Create an immutable object
　　　　Immutable obj = new Immutable("w3codebox,　2011);
　　　　System.out.println("Name: 　"　+　obj.getName());
　　　　System.out.println("Date: 　"　+　obj.getDate());
　　}
}

Output Result

Name: 　w3codebox
Date:　2011

In Java, immutable classes are those whose values do not change. To create an immutable class, please note here:

• The class is declared as final, so it cannot be extended
  

• Class members name and date are declared as private, so they cannot be accessed from outside the class

• Does not contain any setter methods, so external classes cannot change class members

• getter methods return a copy of the class member

• Class members are initialized using the constructor
  

Comprehensive Java Examples