Inheritance

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What Does Inheritance Mean?

Inheritance is a mechanism wherein a new class is derived from an existing class. In Java, classes may inherit or acquire the properties and methods of other classes.

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A class derived from another class is called a subclass, whereas the class from which a subclass is derived is called a superclass. A subclass can have only one superclass, whereas a superclass may have one or more subclasses.

Techopedia Explains Inheritance

Inheritance is the process wherein characteristics are inherited from ancestors. Similarly, in Java, a subclass inherits the characteristics (properties and methods) of its superclass (ancestor). For example, a vehicle is a superclass and a car is a subclass. The car (subclass) inherits all of the vehicle’s properties. The inheritance mechanism is very useful in code reuse. The following are some limitations of Java class inheritance: A subclass cannot inherit private members of its superclass. Constructor and initializer blocks cannot be inherited by a subclass. A subclass can have only one superclass.

The keyword “extends” is used to derive a subclass from the superclass, as illustrated by the following syntax: class Name_of_subclass extends Name_of superclass { //new fields and methods that would define the subclass go here } If you want to derive a subclass Rectangle from a superclass Shapes, you can do it as follows: class Rectangle extends Shapes { …. }

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Margaret Rouse
Senior Editor
Margaret Rouse
Senior Editor

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.