how spring is more efficient than factory pattern in decoupling the classes

Question

one of the most important features of spring is that it provides decoupling using dependency injection. like I have an interface Vehicle and I have its implementations like Car, Bus, Bike. so I can configure these beans in spring and can assign any implementations out of Car, Bus, Bike into Vehicle. so the code is loosely coupled here, but same thing we can achieve here using factory pattern, in this way also we will have to change the code at the only one place while passing the information to the factory method. so I want to know that how spring is more efficient here, I mean why we should use spring if we can achieve same decoupling using factory pattern ?

Answer 1

The difference is that Using Spring or any other IoC Framework will do much more than only create objects (beans in spring terms) for you.

The IoC Controller does:

• Create Objects
• Manage Objects lifetime
• Inject inner dependencies
• allow you to add Scopes

just to name a few things.

Read this blog for more information about IoC with spring, and if you're interested in Scopes read this.

How is Spring more efficient in decoupling the classes?

For Performance Purposes, it really depends on how you implement your Factories. On what you are trying to do.

However it does do a much better Job at decoupling classes. As you can see with all the built in features you can use. So it simplifies many things a lot and does save you a lot of boilerplate code. One thing I want to point out is that it doesn't prevent you from using factories at all, too. For example you can use FactoryBean which provides Factories using the Spring IoC mechanics.