title: class and interface
body: <p>I wonder 3 things.</p>
  
  <p>1: If I have implemented an interface (with a method) in a superclass where im declaring that method, and then I extend that superclass in another class. Then I don't have to redeclare that method right?</p>
  
  <p>2: But if I don't declare that method in the superclass but in the child class then I instantiate the superclass. What happens then? It didn't contain any method from the instance.</p>
  
  <p>3: Could you use implement in a class and then not declaring that method? Maybe it will be used as a superclass only for other classes to extend. And then just declare that method in the child classes or do you have to declare it in the current class you are implementing the interface?</p>