[hiddew]

> Autowiring is against the principles of a typesafe programming language

Constructor autowiring is the application of the inversion of control and dependency injection pattern. If there was no autowiring, you could autowire the components together just the same with normal code calling constructors in the correct order. Spring just finds the components and does the construction for you.

[computerdork]

Yeah, for me at least, personally believe inversion of control should be used more surgically instead of blanketing the system with it. On the one hand, freeing your application layer from direct dependencies with the lower-level objects conceptually seems like a good idea, but think in practice, this is hardly ever helpful especially when used for every dependency.

At least from my experience, seems like we don't change the objects we use that often, that once a object is set on a reference var, a very, very large majority of them won't change.

And because of this, seems like that for most objects dependencies, we should just new them directly, and if later on we do need to change them, then at that time, we can refactor the code to use more abstraction (like inversion of control) to break the direct dependency, but only for the code that needs it (or if there is a important situation where having a direct dependency could be highly problematic in the future, like to a DB provider).

It's like the performance optimization problem. One guideline that is often quoted is that it's best not to over optimize the performance of your code, until you actually can test it in real-world test cases, because you very often optimize things that aren't the bottleneck. Same with the over usage of inversion of control. Spring makes it so we're using IOC everywhere, but it's just adding unnecessary complexity.

Think that if inversion of control is used, should be used mainly at a higher level, for components instead of on every class like often happens. But even for components, think you should be careful when deciding to do so.

... and agreed, you could just use the factory pattern instead of Spring.

[hiddew]

For large applications, having the implementation (or multiple implementations) of certain functionality decoupled from the code using it, improves maintainability and configurability of the application. That is where inversion of control helps. And then manually writing the instatiation, scoping, dependency ordering and cleanup code to manage all of that is not useful to write yourself. Any dependency injection framework will work, although Spring is well used and has many integrations.

[computerdork]

Yeah, I get the idea, abstractions allow decoupling. But, think that it should be used in a thoughtful way - there is quote from the original Design Patterns book that said something like a careful considered use of Design Patterns should make the system easier to work with, or something like that (sorry, don't have it on hand).

We can go back and forth on this, so will just say, in my opinion, Spring autowiring overall doesn't provide enough benefit versus its downsides, which to me are: increased complexity and doesn't work well enough (it should be easier to debug autowiring problems for one).

You seem very knowledgeable about design, and, of course, you're entitled to your opinion, so seems like we'll probably just have to disagree on this:)