[agentgt]

I find this argument sort related to the framework vs library and opinionated vs agnostic.

Being an old fart Java developer I generally prefer things where you can plugin your own implementation (ie agnostic).

That is there is an extreme for killing your dependencies of either extreme copy'npaste OR which every library offers a plugin SPI (ie inversion of control) (or a combo of both).

The problem with the dependency injection above approach (aka Spring prior to Boot) is that you have developers doing lots of custom crap, bloated/overly engineered libraries, increased ramp up time, and configuration hell.

But I still think this is probably better than ole copy'n paste.. most of the time. I do hate dependencies though.

[mwcampbell]

You're probably more experienced in java development than me. But maybe a good rule of thumb is that most Java libraries shouldn't use reflection or dynamically loaded classes (i.e. using Class.forName or ClassLoader). That rules out most dependency injection frameworks.

[agentgt]

That is correct that the libraries should not have DI but I should be able to wire up the library on my own and not let the library do its own static initialization. What is far worse than Class.forName and other crap is libraries self imposed singletons.

Take for example Hystrix. I'm just now fixing that the thing loads up its own configuration framework (Archaius) which uses static initialization. Archaius needed like 10 other dependencies. This is all really because Hystrix uses static singleton (HystrixPlugins) and many frameworks need this or else is incredibly difficult to get an implementation up (ie using pseudo singleton to avoid excessive passing of a context).

https://github.com/Netflix/Hystrix/pull/1083

[lmm]

Java makes plugin-like scenarios very hard. The kind of thing you'd do with a typeclass in languages that have them. There's OSGi (the horror, the horror) which maybe-kinda-sorta-works, or there's the SPI where you put the class name in a .service file (which will then be instantiated though... reflection). When those are the alternatives, DI frameworks aren't so bad.