public static String quote(Object string) {
    if (string == null) {
      return "null";
    }
    return '"' + StringEscapeUtils.escapeJava(string.toString()) + '"';
  }
Returns Java code that can re-create {@code string}: {@code null} if null, or {@code "contents"} if not empty.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/Format.java