• What is access specifier?

It is something that controls the visibility and accessibility of class, methods, and variables.

• Purpose of Access Specifiers?

  1. Enforce Encapsulation
  2. Controlled access:

• Types & explanation for each?

  1. Private:

     1. private variable: inside the class

     2. private method: other methods inside the class can call any of the private method.

     3. you cannot define the access specifier to be private : for a class

        1. For an inner class : you can define it; but can’t do for one which is for the package.

        class ABC{
        	private class XYZ{
        	function();
        	}
        	
        	}
        	
        	//
        	public void update() {
        	XYZ obj = new XYZ();
        	obj.function();
        	}
        

  2. public

     1. methods: it is accessible to the entire world.
     2. variable: It is accessible to the entire world
     3. class: it is accesible to the entire world

     Note: If a class doesn’t have an access specifier : it is package-private by default.

     /* If it is package private :
     outsite the package you will not be able to create an object 
     and if you are not able to create an object
     you will not be able to access the name */
     
     class Account { // this would be package-private
     public string name;
     
     }
     
     /*
     folder name
      - abc.java
      - xyz.java
      */
     
     

  3. Protected. : inside the package & to the subclass of the package 1.

     // Package 1
     
     protected class ABC{
     
     }
     
     class XYZ extends ABC{
     method(){
     ABC obj = new ABC();
     obj.name = 
     
     /* Because it is a private class: we were able to access it. 
     
     // Package 2
     
     protected class DEF{
     method(){
     ABC obj = new ABC()
     }
     }
     
     

1. Package Private : (it is the default) 1.

   class Account {// this is package private
   
   }