Question 1: 

           for (int pos = 0; pos < 2*k; pos+2) {
               L.add(pos, L.get(pos));
           }

Question 2:

           int pos = 0;
           while (pos < L.size()) {
               String str = (String) L.get(pos);
               if (str.equals("hello")) {
                   L.remove(pos);
               }
               else {
                   pos++;
               }
           }

Question 1: 
        public Object remove(int pos) {
            // check for bad pos
            if (pos < 0 || pos >= numItems) throw new IndexOutOfBoundsException();

            // get the item to be removed from pos
            Object ob = items[pos];

            // move items over to fill removed pos
            for (int k = pos; k < numItems-1; k++) {
                items[k] = items[k+1];
            }

            // decrease the number of items
            numItems--;

            // return the removed item
            return ob;
        }

        public Object get(int pos) {
            // check for bad pos
            if (pos < 0 || pos >= numItems) throw new IndexOutOfBoundsException();

            // return the item at pos
            return items[pos];
        }