ACCESS SPECIFIERS/MODIFIERS IN JAVA

ACCESS SPECIFIERS/MODIFIERS IN JAVA

Access Specifier/Modifier in any language defines the boundary and scope for accessing the method, variable and class etc.

Java has defined four types of access specifiers. These are :

1.    Public

2.    Private

3.    Protected

4.    Default

If you do not define any access specifier/modifier than java will take “default” access specifier as the default for variables/methods/class.

SYNTAX For declaring a class with access specifier :

<access-specifier><class-keyword><class-name>

For e.g.

public class Demo

    public access specifier :

If you declare any method/function as the public access specifier than that variable/method can be used anywhere.

public Access Specifier Example :

   package abc;  
   
 public class AccessDemo  
 {  
   
      public void test()  
      {  
            System.out.println("Example of public access specifier");  
      }  
 }  

In any other package if we want to access the class "AccessDemo" then we only need to import the abc package as shown in the following code :

    package xyz;  
 import abc.AccessDemo;  
   
 public class AccessExample  
 {  
   
      public static void main(String[] args)  
      {  
           AccessDemo ad = new AccessDemo();  
           ad.test();  
      }  
 }  

     private access specifier :

If you declare any method/variable as private than it will only accessed in the same class which declare that method/variable as private. The private members cannot access in the outside world. If any class declared as private than that class will not be inherited. :

private Access Specifier Example :

    class AccessDemo   
 {  
       private int x = 56;  
   
      public void showDemo()   
      {  
           System.out.println("The Variable value is " + x);  
      }  
    
      private void testDemo()   
      {  
           System.out.println("It cannot be accessed in another class");  
      }  
 }  
    
   
 public class AccessExample   
 {  
    
      public static void main(String[] args)   
      {  
           AccessDemo ad = new AccessDemo();  
           ad.testDemo(); // Private method cannot be used  
           ad.x = 5; // Private variable cannot be used  
    
           ad.showDemo(); // run properly  
      }  
 }  
   

    default access specifier :

If you define any method/variable as default or not give any access specifier than the method or variable will be accessed in only that package in which they are defined.

They cannot be accessed outside the package.

default Access Specifier Example :

In one package we define the variable default as below code :

    package abc;  
   
 class AccessDemo   
 {  
      default int a = 4;  
 }  

Now in any other package if we want to change the value of a, it is not possible because the other package has not access permission for "a" variable.

 package xyz;  
 import abc.AccessDemo;  
   
   
 class AccessExample   
 {  
      public static void main(String[] args)  
      {  
           AccessDemo ad = new AccessDemo();  
           ad.a = 67; //It is not possible.  
      }  
 }  

    protected access specifier :

It has same properties as that of private access specifier but it can access the methods/variables in the child class of parent class in which they are declared as protected.

When we want to use the private members of parent class in the child class then we declare those variables as protected.

protected Access Specifier Example :

 class AccessDemo   
 {  
      protected int x = 34;  
    
       public void showDemo()   
      {  
            System.out.println("The variable value is " + x);  
       }  
 }  
    
 class ChildAccess extends AccessDemo  
 {  
       // child class which inherits  
       // the properties of AccessDemo class  
 }  
    
 public class AccessExample   
 {  
    
       public static void main(String[] args)   
      {  
            ChildAccess ca = new ChildAccess();  
    
            ca.showDemo(); // run properly  
            ca.x = 45; // run properly  
 }   
 }