Angular $provide and $injector

While reading the $provide and $injector service, I extract following from angular document for quick retrieving:

To wrap it up, let’s summarize the most important points:

• The injector uses recipes to create two types of objects: services and special purpose objects
• There are five recipe types that define how to create objects: Value, Factory, Service, Provider and Constant.
• Factory and Service are the most commonly used recipes. The only difference between them is that the Service recipe works better for objects of a custom type, while the Factory can produce JavaScript primitives and functions.
• The Provider recipe is the core recipe type and all the other ones are just syntactic sugar on it.
• Provider is the most complex recipe type. You don’t need it unless you are building a reusable piece of code that needs global configuration.
• All special purpose objects except for the Controller are defined via Factory recipes.

* at the cost of eager initialization by using new operator directly
** the service object is not available during the config phase, but the provider instance is.