code: public static <E> Iterator<E> cycle(Iterable<E> iterable) {
          dbc.precondition(iterable != null, "cannot cycle a null iterable");
          return new CyclicIterator<E>(iterable.iterator());
      }
docs: Creates an infinite iterator that issues elements from the parameter cyclicly.
  
  @param <E> the element type
  @param iterable the iterable to cycle
  @return an iterator that cyclicly returns the elements from the argument