guice

> First: constructor calling is not readable because Java misses named parameters. It's fine when there are 2-3 dependencies, but not more. If you have more than 2-3 dependencies, it might be time to refactor things, as your class may be doing too many things. > Second: circular dependency is not possible. Circular dependencies are possible with constructor injection when using a DI framework (e.g., using a Provider in Guice [1], or the equivalent in Dagger). [1] https://github.com/google/guice/wiki/CyclicDependencies

The specific systems I'm thinking of were Google-internal, but there's a close public analogue with Guice & Dagger: https://github.com/google/guice https://github.com/square/dagger Imagine injecting Futures into your code. Now imagine injecting them, but having the Provider record a lot of metadata about who you were calling, how you were calling it, how long it took, whether an error occurred, letting an SRE turn off the call, etc.