Injecting business classes into businsess classes in a three layered architecture

Question

I have a three layered Java application consisting of a presentation layer, a business layer, and a data access layer. In my application, the business layer contains what I am calling service classes and my data access layer contains what I'm calling data access classes. I am using Spring for dependency injection and to manage database transactions from the business layer down.

I have been wondering lately if it is a "normal" practice to inject service classes into other service classes. The reason I am asking is that I have a service class that contains logic that I would like to use in other service classes and I do not want to duplicate the logic only to avoid injecting a service class into another service class. I'm worried about circular references between the service classes. To avoid doing this, I was going to create a facade to wrap up the logic that I need, but I figured I'd ask the community first.

Answer 1

How are your services connected to (obtained from) presentation layer? Are you injecting them as well or are you using some sort of service locator pattern?

I would normally go with the latter for both presentation layer and service layer, e.g. service1 that needs to call service2 would obtain it via service locator.