private static void append(StringBuilder sb, DisplayMode mode) {
    sb.append("mode: ").append(mode.getWidth()).append("x").append(mode.getHeight());
    sb.append("; bit depth=").append(mode.getBitDepth());
    sb.append("; refresh rate=").append(mode.getRefreshRate());
    sb.append("\n");
  }
private static void append(StringBuilder sb, DisplayMode mode)