title: Real world example of application of the command pattern
body: <p><a href="http://en.wikipedia.org/wiki/Command_pattern" rel="noreferrer">Command pattern</a> can be used to implement <code>Transactional behavior</code> (and <code>Undo</code>).<br>
  But I could not find an example of these by googling. I could only find some trivial examples of a lamp that is <code>switched on</code> or <code>off</code>.<br>
  Where can I find a coding example (preferably in <code>Java</code>)of this/these behaviors implemented using the <code>Command Pattern</code>?</p>