title: How to get uuid or mac address from client in Java?
body: <p>I'm looking for a solution for a Java based webapplication to uniquely identify the client. The server is in the same network as the clients and I thought that using the MAC address would be a good solution. 
  The problem is I can't work with cookies because they can be deleted client-side and I can't use the IP because they could just issue a new DHCP lease renewal.</p>
  
  <p>So I would like to fallback to the MAC address of the clients. I'm aware that there is no java built in feature to get the MAC address.
  Is there a library that can handle the output of every OS? (primary Windows and Mac) since my java Application runs on both platforms.</p>
  
  <p>or are there any other suggestions for uniquely identifying a client within a website and the HTTP Protocol ? (maybe HTML5 data stores or something else)</p>
  
  <p>I'm using Java 1.7 btw.</p>
  
  <p>I won't force the user to login or otherwise identify himself and I won't program a native app for the clients smartphone.</p>