Access Modifiers in Java

Access Modifiers in Java specifies the level (or scope) of access to classes, variables, methods and constructors. There are four access modifiers in Java:

  1. Private
  2. Protected
  3. Default (no keyword is used)
  4. Public

Public Access Modifier:

Public means available to all. Public classes, methods, variables and constructors are accessible everywhere within the project.

Example:

Let us consider a class – ClassA which has two integer variables – firstNum and secondNum – both defined as public and a method addTwoNumbers(), again defined as public.

Another class with ClassB is defined in which a variable (instance) of ClassA is created and as the variables and methods defined in ClassA are public, all of them are accessible here. Refer below code:

Let us look at another scenario where ClassA is extended by ClassC. Here also all the methods and variables which are public are accessible. Refer below code:

Private Access Modifier:

Private methods and variables can be accessed within same class only. They are not accessible outside the class.

Protected Access Modifier:

Protected methods, variables and constructors can be accessed within the same package via both means (calling from the instance of a class or via Inheritance) but outside a package, they can be accessed only via Inheritance.

Note: Classes cannot be private or protected, they can only be public or default.

Default Access Modifier:

No keyword is used for default access modifier. Methods, variable and constructors can be accessed within the same package only via both ways (creating an instance of a class or via inheritance) but outside a package, it cannot be accessed via any means.

 

 

Saurabh Dhingra

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