### Question:
SinglyLinkedList implements List<E> { @Override public void add(int i, E e) { }  @Override boolean isEmpty(); @Override E get(int i); @Override void add(int i, E e); @Override E remove(int i); @Override Iterator<E> iterator(); @Override int size(); @Override E removeFirst(); @Override E removeLast(); @Override void addFirst(E e); @Override void addLast(E e); static void main(String[] args);  }### Answer:
@Test void testAdd() { SinglyLinkedList<Integer> ll = new SinglyLinkedList<>(); for(int i = 0; i < 5; ++i) ll.addLast(i); ll.add(2, -1); assertEquals("[0, 1, -1, 2, 3, 4]", ll.toString()); }