private static String externalizeFileName(CharSequence classOrPackageName, CharSequence... suffix) {
    StringBuilder buf = new StringBuilder();
    for (int i = 0, len = classOrPackageName.length(); i < len; i++) {
      char ch = classOrPackageName.charAt(i);
      buf.append(ch == '.'? '/' : ch);
    }
    for (CharSequence s : suffix) {
      buf.append(s);
    }
    return buf.toString();
  }
private static String externalizeFileName(CharSequence classOrPackageName, CharSequence... suffix)