code: public static <T, L extends List<T>> L requireNonNullEntries(final L collection, final String argumentName) {
          requireNonNull(collection, argumentName);
          final String msg = String.format(NOT_NULL_ENTRIES_MSG_FORMAT, argumentName);
          for (final Object value : collection) {
              requireState(value != null, msg);
          }
          return collection;
      }
docs: Checks whether the specified {@code collection} contains null values, throws {@link IllegalStateException} with a customized error message if it has.
  
  @param collection   the collection to be checked.
  @param argumentName the name of the argument to be used in the error message.
  @return the {@code collection}.
  @throws java.lang.NullPointerException  if {@code collection} is null.
  @throws java.lang.IllegalStateException if {@code collection} contains null values.
  @see #requireNonNull(Object, String)