title: How to add a single key shortcut to a JMenuItem
body: <p>I am creating a simple text editor similiar to Notepad.
  It would insert the time and date to the file if the user presses <kbd>F5</kbd>.
  I browsed about mnemonics and accelerators but they are used in combination with <kbd>Alt</kbd> and <kbd>Ctrl</kbd> respectively. </p>
  
  <p>Should I use an <code>EventListener</code> or is there any other solution?</p>