esents the percent sign character '%'</li>
 </ul>
 <p>
 Normally, the generation numbers are not larger than the given file count and
 follow the sequence 0, 1, 2.... If the file count is larger than one, but the
 generation field("%g") has not been specified in the pattern, then the
 generation number after a dot will be added to the end of the file name.
 <p>
 The "%u" unique field is used to avoid conflicts and is set to 0 at first. If
 one <code>FileHandler</code> tries to open the filename which is cur