Currently, injected dependencies whose field declaration type is an interface are ignored when using "fullyInitialized = true" and there is no matching @Injectable.

To support such dependencies, we can try and find an already loaded class which implements the interface, in order for it to be instantiated. If more than one such class is found, however, the dependency would still be left null. This way, test code can choose which implementation class to use by simply ensuring the class is loaded by the JVM.