code: protected static String getFileName(String file_name) {
      if (file_name == null) return "";
      file_name = file_name.trim();
      int iPos = 0;
      iPos = file_name.lastIndexOf("\\");
      if (iPos > -1) file_name = file_name.substring(iPos + 1);
  
      iPos = file_name.lastIndexOf("/");
      if (iPos > -1) file_name = file_name.substring(iPos + 1);
  
      iPos = file_name.lastIndexOf(File.separator);
      if (iPos > -1) file_name = file_name.substring(iPos + 1);
  
      return file_name;
    }
docs: Returns the file name by path.
  
  @param file_name