Using Callback handelr to get Username

Question

For my JSF project I have a httpSessionListener which works fine on session Timeout.
In the sessionDestroyed() method I have to get the User name of the user that was timed out.
I have to use Call back handler for that. The problem is that i am always getting the username as null and also the callback handler is null.
My listener class is as follows :
public class myHttpSessionListener  extends DBTableOraDataSourceLoginModule implements HttpSessionListener
// callback handler settings
  static final int NUM_CALLBACKS = 2;
  static final int USERNAME_CALLBACK_INDEX = 0;
  static final int PASSWORD_CALLBACK_INDEX = 1;
  String username = null; protected CallbackHandler callbackHandler = super._callbackHandler;
public void sessionDestroyed(HttpSessionEvent sessionEvent)
// Get the session that was invalidated
HttpSession session = sessionEvent.getSession();
if (callbackHandler == null)
Utility.logMessage(Constants.SEVERITY_INFO,
"******* CallBack Handler is NULL ********", this);
Callback[] callbacks = new Callback[NUM_CALLBACKS];
callbacks[USERNAME_CALLBACK_INDEX] = new NameCallback("Username");
callbacks[PASSWORD_CALLBACK_INDEX] = new PasswordCallback("Password:",false);
try
callbackHandler.handle(callbacks);
username =
((NameCallback) callbacks[USERNAME_CALLBACK_INDEX]).getName();
catch (UnsupportedCallbackException e)
Utility.logMessage(Constants.SEVERITY_INFO,
"^^^^^^^^^ UnsupportedCallbackException() ********" + e , this);
catch (IOException ie)
Utility.logMessage(Constants.SEVERITY_INFO,
"^^^^^^^^^ IOException() ********" + ie , this);
Utility.logMessage(Constants.SEVERITY_INFO,
"SessionDestroyed() ******** UserName = " + username , this);
}Thanks in advance .....                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

Answer 1

In java we have one method of System class to get the properties of system.
System.getProperty(String propName)
To get the user name , we can use the property name : user.name
System.getProperty("user.name")
which returns the current working user name of the system..
try it out.
Regards