Today we are going to see one of the design patterns abstract factory. Its one level of abstraction higher than factory pattern.The main use of Abstract Factory Patten is that is isolates the concrete classes which are generated.

Singletons are the design pattern when you want only one instance of a class created. You make the constructor private, and give access to the instantiated object via a static instance method that creates the object if it has not been created already. The singleton class is threadsafe lazy instantiation. I hope many would be [...]