Access Modifiers

Java provides with various access modifiers to class, methods, variables, constructors to set access level and control who can access which variables or class or methods.

The Access levels are divided into below categories

• Public >> Access to everyone
• Private >> Access to enclosing class
• Protected >> Access to all subclass and within the package
• default >> Access to all classes within the package

Lets see how these modifiers affect the its functionality when applied to different key aspects of JAVA

	Public	Private	Protected	Default (No modifier)
Class	Acesss to everyone	NA	NA	Access to classes within package
Variable	Acess to everyone	Access to enclosing class members	Access within package and subclass	Access to classes within package
Method	Acess to everyone	Access to enclosing class members	Access within package and subclass	Access to classes within package
Constructor	Acess to everyone	Access to enclosing class members	Access within package and subclass	Access to classes within package

There is another keyword “final” which can be applied to a Class, Variable, Method. Although it does not determine the access but it has great significance.

When applied to a class it means, the class cannot be subclassed, i.e. extending a class marked final is not possible. A small example is described below. The keyword can be placed before or after the access modifier.

public final class Car {
}

The final keyword when applied to method of a class, makes the method final and does not allow the subclasses to be override.

And the final keyword when applied to a variable implies that the variable cannot be reassigned to a new instance once it is assigned a value.

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