In this chapter, we will introduce a small but fake service called the ACME registration service. The code for this service will serve as the basis for most of the examples in the rest of the book. We will examine the business environment in which this service lives, discuss the goals for the service and the code, and finally, we will look at some examples of the problems that we can fix by applying dependency injection (DI).

By the end of this chapter, you should have enough knowledge to join the team as we work our way through the improvements we will make in the following chapters.

The following topics will be covered in this chapter:

• Goals for our system
• Introduction to our system
• Known issues