title: What is the advantage of using interfaces
body: <p>Let's say you have an interface</p>
  
  <pre><code>public interface Change {
  
      void updateUser();
      void deleteUser();
      void helpUser();
  
  }
  </code></pre>
  
  <p>I've read that interfaces are Java's way to implement multiple inheritance. You implement an interface, then you have access to its methods. What I don't understand is, the methods don't have any body in the interface, so you need to give them a body in your class. So if you an interface is implemented by more than one class, you need to give the method a body in more than one class. Why is this better than just having individual methods in your classes, and not implementing an interface?</p>