Java 8: Static interface methods considered with FactoryModuleBuilder #937

Consider the following assisted inject factory interface:

public interface Factory {
    Impl build();

    static Factory getDefault() {
       // ...
    }
}

This is, of course, permissible in Java 8 as you can associate static methods with interfaces. However, when you use FactoryModuleBuilder on it, as so:

install(new FactoryModuleBuilder().build(Factory.class));

There is an error along the lines of the following:

Factory is an interface, not a concrete class. Unable to create AssistedInject factory.

This does not seem to be intuitive, because Factory is supposed to be an interface. Debugging this code reveals that this is in reference to the static method, which should, by all means, not be considered because of its static-ness. Indeed, FactoryProvider2's constructor does not appear to skip over static methods, as expected.

Of course, a workaround exists simply by moving the static method away from the factory interface, but this seems like a bug in the functionality of FactoryProvider2 specifically.