Data Hiding,Abstraction and Encapsulation

Data Hiding

Outside person can’t access our internal data directly or internal data variable can’t be access directly from outside. This feature of oops is called Data hiding. We can access these variables through methods.
The main advantage of this feature is to provide Security. 

We can achieve this feature by declaring our variable as private variable.

Abstraction

Hiding the internal implementation and just Highlighting the set of Service is called Abstraction.

We can achieve the Abstraction by using Abstract class or interface in our program.

The main advantage of these feature are:

1.      We can achieve the security to next level.
2.       Enhancement of the system becomes easy without affecting the end user.
3.       It improves the maintainability of the system.
4.       It provides more flexibility to end user to use system easily.

Encapsulation

The process of binding data members (variables) and methods into a single unit is called Encapsulation.

Technically if any unit follows data hiding and abstraction then we say this unit follows encapsulation and it is encapsulated.

Encapsulation = Data Hiding + Abstraction

Advantage of encapsulation is similar as Abstraction.

The Disadvantage of encapsulation is it increases the length of code and execution time will increase.

Tightly encapsulated

A class is said to be tightly encapsulated if and only if  each variable of the class is declared to be private whether class contain corresponding setter and getter or not and  whether these methods declare public or not.
                It means for tightly encapsulation all variable must be private only.
If the parent class is not tightly encapsulated then its child class also not tightly encapsulated even if it declare its all variable as private.