I have a subclass called Passenger which is extending from a Person class. I want to make the Passenger class a observable object. So I do it in this way,

```
class Person extends Observable{    
}

class Passenger extends Person{
    public void move(){
        setChanged();
        notifyObservers();
    }   
}

class Manager implements Observer{
    @Override
    public void update(Observable o, Object arg) {
    }  
}

```

Is it a bad practice to make the Person class Observable when I don't need observable functionality for that class? If so how can I change this?