About Question com.enthuware.ets.scjp.v6.2.94 :

[Juan Andrés Calleja]

Hello, in the fifth option


class MidiPlayer implements MusicPlayer<Instrument> {
public void play(Guitar g){ }
}

the explanation says:


"Since MusicPlayer is typed to Instrument here, MidiPlayer must have a method play(Instrument)"


Is true that MusicPlayer is typed to Intrument, but in the exercise, MusicPlayer interface extends Player interface in RAW mode (without using generics).


interface MusicPlayer<E extends Instrument> extends Player{ }


So in practice i think that the correct explanations should be this:

"Since MusicPlayer is typed to Instrument here, MidiPlayer must have a method play(Object)"

So, but if you really wish maintain the explanation that exercise show, the interface Music Player should be fixed like this:


interface MusicPlayer<E extends Instrument> extends Player<E>{ }


The explanation in this case would be correct.

I hope I have explained correctly.

[admin]

You are right. The explanation has been updated accordingly.
thank you for your feedback!