Encapsulation

Encapsulation is the mechanism that binds together code and the data if manipulates, and keeps both safe from outside interference and misuse. One way to think about encapsulation is as a protective wrapper that prevents the code and data from being arbitrarily accessed by other code defined outside the wrapper. Access to the code and data inside the wrapper is tightly controlled through a well-defined interface. Conclusion: The wrapping up of data and methods into a single unit (called class) is known as encapsulation.

Inheritance

Inheritance is the process by which object of one class acquires the properties of another class. Inheritance supports the concept of hierarchical classification. For example, the atlas is a part of class bicycle, which is again a part of the class cycle. As illustrated in the principal behind this sort of division is that each derived class shares common characteristics with the class from which it is derived. In OOP, the concept of inheritance provides the idea of reusability. This means that we can add additional features to an existing class without modifying it. This is possible deriving a new class from the existing one. The new class will have the combined features of both the classes. Thus the real appeal and power of the inheritance mechanism is that allows the programmer to reuse a class that is almost, but not exactly, what he wants, and to tailor the class is such a way that is does not introduce any undesirable side effects into the rest of the class. The drive class is knows as 'subclass'.

Polymorphism

Polymorphism is a feature that allows one interface to be used for a general class of actions. The specific action is determined by the exact nature of the solution. Polymorphism means the ability to take more than one form. For example, consider the operation of addition. For two numbers, the operation will generate the sum. If the operands are three numbers, then the operation would produce the product of them. That a single function name can be used to handle different number and different arguments. This is something similar to a particular word having several different meanings depending on the context. Polymorphism plays an important role in allowing objects having different internal structures to share the same external interface. This means that a general class of operations may be accessed in the same manner even though specific actions associated with each operation may differ. Polymorphism is extensively used in implementing inheritance.