How this works/processed?

@Inject
    protected ObjectFactory getObjectFactory() {
        throw new UnsupportedOperationException(); // << not thrown during execution?
    }

Would inject work just for ObjectFactory field ?

Basically, Gradle will create a subclass that overrides the method to return an

ObjectFactory

and that won't call the

super

method, so won't throw. It works for a handful of services: https://docs.gradle.org/current/userguide/custom_gradle_types.html#service_injection It's more idiomatic nowadays to make the class and method abstract (and then you don't have to annotate it with

@Inject

) but Gradle itself still uses that approach a lot.

That was the second question, reading all Tasks sources and see that most of them abstract. Was bit confusing

Since when do you not need

@Inject

@Thomas Broyer? You still need it even when using an interface or abstract methods, don't you?

Oops! I got things mixed up with managed properties I think. Indeed you still need the

@Inject

, and this is documented in the link I gave above 🤦‍♂️ 🤣