System.arraycopy(source, 0, dest, pos, source.length);
  }

  /** ImmutableList.of API that is friendly to use from JavaScript. */
  @JsMethod(name = "of")
  static <E> ImmutableList<E> jsOf(E... elements) {
    return copyOf(elements);
  }

  public static <E> ImmutableList<E> copyOf(Iterable<? extends E> elements) {
    checkNotNull(elements); // for GWT
    return (elements instanceof Collection)