code: public synchronized E pop() {
          E       obj;
          int     len = size();
  
          obj = peek();
          removeElementAt(len - 1);
  
          return obj;
      }
docs: Removes the object at the top of this stack and returns that
  object as the value of this function.
  
  @return  The object at the top of this stack (the last item
  of the <tt>Vector</tt> object).
  @throws  EmptyStackException  if this stack is empty.