Program to demonstrate how to make and code a Java Class Immutable
package com.hubberspot.example;
// 1. Create a class with final keyword
// so that no other class can extend this
// class, to change the state of class
final class Product {
// 2. Create variables with final keyword
// so that once values are assigned to it
// they cannot be modified
private final String name;
private final int count;
// 3. Create a public constructor which sets
// the state of these variables
public Product(String name, int count) {
this.name = name;
this.count = count;
}
// 4. Generate only the getters method and
// no setters, so that no application calling class
// can change the state of variables
public String getName() {
return name;
}
public int getCount() {
return count;
}
}
public class ImmutableExample {
public static void main(String[] args) {
// 5. Create a Product and assign values in
// its constructor
Product product = new Product("pen" , 1);
System.out.println(product.getName());
System.out.println(product.getCount());
// 7. No way for the application class
// to change the state of Product class
// as there are no setters or a way to
// extend the final class , thus immutable
// class is created
}
}
Video tutorial to demonstrate how to make a Java class immutable.
