throws Throwable
  public static String ltrim(Env env,                             String string,                             @Optional String characters)    throws Throwable  {    boolean []trim;    if (characters.equals(""))      trim = TRIM_WHITESPACE;    else      trim = parseCharsetBitmap(characters);    for (int i = 0; i < string.length(); i++) {      char ch = string.charAt(i);      if (ch >= 256 || ! trim[ch]) {        if (i == 0)          return string;        else          return string.substring(i);      }    }    return "";  }