Consider the following case of inheritance:

public class ExtendingHashSet<E> extends HashSet<E>  {
   private int counter = 0;

   public ExtendingHashSet() {

   }

   @Override
   public boolean add(E e)  {
      counter++;
      return super.add(e);
   }

   @Override
   public boolean addAll(Collection&lt;? extends E&gt; c)  {
      counter += c.size();
      return super.addAll(c);
   }

   public int getCounter()  {
      return counter;
   }
}

Created instance:

ExtendingHashSet<String> s = new ExtendingHashSet<String>();
s.addAll(Arrays.asList("one", "two", "three"));

Question: What value would s.getCounter() method return at this point and why?

Looking forward for your answers dear readers