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)

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