Whenever we are writing our classes we have to provide some information about our classes to the JVM like whether this class can be accessed from anywhere or not, whether child class creation is possible or not, whether object creation is possible or not etc. we can specify this information by using an appropriate keyword in java called access modifiers. So access modifiers are used to set the accessibility of classes, methods, and other members.
Private Access Modifiers:
This modifier is not applicable for top-level classes or interfaces. It is only applicable to constructors, methods, and fields inside the classes. If a variable or methods or constructor is declared as private then we can access them only from within the class i.e from outside the class we can’t access them.
Java
// Java Program to illustrate Private Access Modifier // import required packagesimport java.io.*; import java.util.*; // helper classclass A { // helper method private void m1() { System.out.println("GFG"); }} // driver classclass B { // main method public static void main(String[] args) { // creating an object of type class A A a = new A(); // accessing the method m1() a.m1(); }} |
Final Access Modifier:
It is a modifier applicable to classes, methods, and variables. If we declare a parent class method as final then we can’t override that method in the child class because its implementation is final and if a class is declared as final we can’t extend the functionality of that class i.e we can’t create a child class for that class i.e inheritance is not possible for final classes. Every method present inside the final class is always final y default but every variable present inside the final class need not be final. The main advantage of the final keyword is we can achieve security and we can provide a unique implementation. But the main disadvantage of the final keyword is we are missing key benefits of OOPs like Inheritance(Because of the final class), Polymorphism(Because of the final method) hence if there are no specific requirements then it is not recommended to use the final keyword.
Java
// Java program to illustrate Final keyword// import required packagesimport java.io.*;import java.util.*;// Declaring parent class Pclass P { // Declaring a first name // method public void firstName() { // Display firstname System.out.println("Rahul "); } /// Declaring a final surName // method public final void surName() { // Display surname System.out.println("Trivedi"); }}// Creating a child class// of above parent classclass C extends P { // overriding the surName // method public void surName() { // Display surname System.out.println("Sharma"); } // Main method public static void main(String[] args) { // Display message System.out.println("GFG"); }} |
| Private Access Modifier | Final Access Modifier |
|---|---|
| This modifier is not applicable to top-level classes. | This modifier is applicable to top-level classes. |
| We cannot access private methods outside the class. | We can access the final method outside the class. |
| We can hide the private method. | The final method cannot be hidden. |
| This modifier is applicable to both the enum and constructor. | The final modifier is not applicable to both the enum and constructor. |
| This modifier is not applicable for local variables. | The final modifier is the only modifier which is applicable for local variables. |
