code: public static <T> Collection<T> notNullElements(Collection<T> list, String name) {
          notEmpty(list, name);
          for (T ele : list) {
              notNull(ele, String.format("Collection %s element %s", name, ele));
          }
          return list;
      }
docs: Check that a list is not null and that none of its elements is null. If null or if the list has emtpy elements
  throws an IllegalArgumentException.
  @param list the list of T.
  @param name parameter name for the exception message.