OOPs revolve around the four concepts:

1. Encapsulation
2. Polymorphism
3. Abstraction
4. Inheritance

In OOPs, these concepts are implemented through a class definition and achieved through the object creation process, programmatically.

Here we will discuss Inheritance briefly: 

-- Inheritance is the mechanism to organize and structure the software program in an hierarchical manner. 
-- Through inheritance a new class can inherit some existing behavior and states of another class. This promotes the concept of code reusability.
-- Inheritance saves work as the already existing class allows the new class to inherit all the properties of the old general class and as a programmer you only require the new features. 
-- Inheritance  allows various objects to share certain things common by allowing to define a general class and later to organize some other classes simply adding some details with the old class definition.
-- Inheritance  allows a better data analysis, reduction in development time, less coding and better performance.

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www.roseindia.net/java/beginners/oop-in-java.shtml