Factory Design Pattern

Factory pattern

Polymorphism extensibility

What is the worst keyword in Java from polymorphism angle

• final
• instanceof
• static

new

new ClassNAme() //tight coupling So many patterns to fight with new, especially in Spring

new introduces tight coupleing. New is not poluymorphic in Java, C++, .Net but its is Ruby

Python or Kotlin doesn’t even have new

Golden Rule : interfaces are better than abstract classes

Interfaces can have implementations (default methods) however they cannot have non final fields Interfaces cannot carry state but an abstract class carry a state.

Abstract Factory vs. Factory Method

Class vs method

Factory Method : A class or an interface relies on a derived class to provide the implementation whereas the base provides the common behavior

uses inheritance as design tool uses factory METHOD

Abstract Factory uses delegation as design tool