What is abstract method
Answer: An abstract method is a method that is declared without an implementation (without braces, and followed by a semicolon), like this:
If a class includes abstract methods, then the class itself must be declared abstract, as in:
When an abstract class is subclassed, the subclass usually provides implementations for all of the abstract methods in its parent class. However, if it does not, then the subclass must also be declared abstract.