Factory design pattern is used when we have a super class with multiple sub-classes and based on input, we need to return one of the sub-class. This pattern take out the responsibility of instantiation of a class from client program to the factory class. Let’s first learn how to implement factory pattern in java and then we will learn its benefits and we will see its usage in JDK.

* Super Class

Super class in factory pattern can be an interface, abstract class or a normaljava class. For our example, we have super class as abstract class with overridden toString() method for testing purpose.

see `com.factory`.

* sub-classes

Let’s say we have two sub-classes PC and Server with implementation in `com.factory`

Here's what we have in image :

Now let's write the test class.