if (Character.isJavaIdentifierStart(cn.toCharArray()[0])) abort("");
if (! Character.isJavaIdentifierStart(t.toCharArray()[0])) abort("Class name [" + cn + "] contains an invalid sub-package identifier: " + t);
  private String validateClassName(String cn) throws IOException  {    if (cn.startsWith(".") || cn.endsWith("."))      abort("MODULE_CLASS MUST NOT start or end with a '.'");    String[] tokens = cn.split(".");    for (int i = 0; i < tokens.length; i++)      {        String t = tokens[i];        if (Character.isJavaIdentifierStart(cn.toCharArray()[0]))          abort("");        // we dont check the rest of the characters for isJavaIdentifierPart()        // because that's what the tokenizer does.      }        return cn;  }