public static String join(CharSequence delim, Object... parts) {
    StringBuilder result = new StringBuilder();
    for (int i = 0; i < parts.length; i++) {
      if (i != 0) {
        result.append(delim);
      }
      result.append(Objects.toString(parts[i]));
    }
    return result.toString();
  }
@return the object, represented as a URL value (not URL encoded).
src/main/java/com/google/maps/internal/StringJoin.java