Difference between Abstract Class and Interface

Abstract Class
  • Abstract class provides a set of rules to implement next class
  • Rules will be provided through abstract methods
  • Abstract method does not contain any definition
  • While inheriting abstract class all abstract methods must be override
  • If a class contains at least one abstract method then it must be declared as an “Abstract Class”
  • Abstract classes can be instantiated, but a reference cannot be created
  • Reference depends on child class object’s memory
  • Abstract classes are also called as “Partial abstract classes”
  • Partial abstract class may contain functions with body and functions without body
  • If a class contains all functions without body then it is called as “Fully Abstract Class” (Interface)
  • If a class contains all abstract methods then that class is known as “Interface”
  • Interfaces support like multiple inheritance
  • In interface all methods r public abstract by default
  • Interfaces r implementable
  • Interfaces cannot be instantiated, but a reference can be created