title: How to detect if a Java System property has changed?
body: <p>I would like to know when a System property is changed. I have an application, in an application server, that somehow is changing a system property (<code>System.setProperty()</code> I think). I was taking a look and I have found different approaches:</p>
  
  <ol>
  <li><a href="https://stackoverflow.com/questions/5410054/attach-to-another-jvm-and-listen-for-events-possible">JPDA?</a></li>
  <li><a href="https://stackoverflow.com/questions/4130673/triggering-events-in-java-when-an-objects-state-changes">Observer &amp; Observable?</a></li>
  <li><a href="http://docs.oracle.com/javase/tutorial/uiswing/events/propertychangelistener.html" rel="nofollow noreferrer">Property change listener?</a></li>
  <li><a href="http://java.sun.com/developer/technicalArticles/J2SE/jmx.html" rel="nofollow noreferrer">JMX?</a></li>
  </ol>
  
  <p>Any suggestions?  Thanks in advance.</p>