What is the difference between Factory and Service?

“Factory” and “Service” are different ways of doing DI (Dependency injection) in angular. Please read the previous question to understand what is DI.
So when we define DI using “service” as shown in the code below. This creates a new GLOBAL instance of the “Logger” object and injects it in to the function.

app.service("Logger", Logger); // Injects a global object

When you define DI using a “factory” it does not create a instance. It just passes the method and later the consumer internally has to make calls to the factory for object instances.

app.factory("Customerfactory", CreateCustomer);

Below is a simple image which shows visually how DI process for “Service” is different than “Factory”.

	Factory	Service
Usage	When we want to create different types of objects depending on scenarios. For example depending on scenario we want to create a simple “Customer” object , or “Customer” with “Address” object or “Customer” with “Phone” object. See the previous question for more detailed understanding.	When we have utility or shared functions to be injected like Utility , Logger , Error handler etc.
Instance	No Instance created. A method pointer is passed.	Global and Shared instance is created.