code: public static <T> List<T> getRandomSublist(List<T> list, int count) {
  		Validate.smallerEqual(count, list.size());
  		List<T> opSet = new ArrayList<>(list);
  		Collections.shuffle(opSet);
  		return ListUtils.copyOfRange(opSet, 0, count-1);
  	}
docs: Generates a random sublist of <code>list</code>, that contains exactly
  <code>maxCount</code> elements.
  
  @param <T>
  Type of list elements
  @param list
  Basic list for operation
  @param count
  Number of items
  @return A sublist with exactly <code>count</code> elements