Factory Design Pattern
A factory method pattern is a creational pattern. It is used to instantiate an object from one among a set of classes based on a logic.

Assume that you have a set of classes which extends a common super class or interface. Now you will create a concrete class with a method which accepts one or more arguments. This method is our factory method. What it does is, based on the arguments passed factory method does logical operations and decides on which sub class to instantiate. This factory method will have the super class as its return type. So that, you can program for the interface and not for the implementation.