Actually i too got it wrong and convinced myself that "HAS-A" makes sense only with instance variables. Though i am not completely convinced
Lets try this example (though not a perfect one)
Lets say Honda always have a particular kind of audio system (Bose) and this will never change (Remember its not a perfect example).
class Honda {
final static BoseSpeakerSystem speaker = new BoseSpeakerSystem();
//can override other functions
...
...
...
}
class BoseSpeakerSystem extends SpeakerSystem{
}
In this case can we say all Honda cars have a Bose Speaker System?