Difference between Dependency Injection and Factory Pattern.

Factory and Dependency injection both are the design pattern which can be used to enhance loose coupling abilities between the software components. 

Factory design pattern is used to create objects. But, injection and life cycle management of the object should be handled by programmer within the application. There is no way to configure everything in a single place. Therefore, programmers need to call object creation logic wherever it needed which eventually hinder the loose coupling abilities.

In DI design pattern, creation of object, injecting of the instance and life cycle management of the instance can be handled outside the code. In spring, Instantiation ,Injection and Lifecycle management are handled by IOC container.

Example of Factory pattern

static class PizzaFactory{
   public Pizza buildPizza(String pizzaType){
      ........

      Pizza pizza= //create pizza based on type
      return pizza;
   }
}
static void Main(){
   Pizza pizza = PizzaFactory.buildPizza("Greek style");
}

Example of Dependency Injection

public class CustomerExample {
   public Address address
   public CustomerExample(Address address) {
      this.address = address;
   }
}
public class Address {
   ..............
}