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Abstract Class


An Abstract class is a class that provides a common definition to the subclasses and this is the type of class whose object is not created.

key points of Abstract classes are:
  • Abstract classes are declared using the abstract keyword.
  • We cannot create an object of an abstract class.
  • If you want to use it then it must be inherited in a subclass.
  • An Abstract class contains both abstract and non-abstract methods.
  • The methods inside the abstract class can either have an implementation or no implementation.
  • We can inherit two abstract classes; in this case the base class method implementation is optional. 
  • An Abstract class has only one subclass.
  • Methods inside the abstract class cannot be private.
  • Abstract classes are useful when you need a class for the purpose of inheritance and polymorphism.
  • The purpose of an abstract class is to provide default functionality to its subclasses
  • When a class contains at least one abstract method, then the class must be declared as an abstract class
  • It is mandatory to override the abstract method in the derived class
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