private Roster getRoster() {
        try {
            return XMPPServer.getInstance().getRosterManager().getRoster(userJID.getNode());
        } catch (UserNotFoundException e) {
            Log.warn("Roster not found for user: " + userJID);
        }
        return null;
    }
Sets the new list items based on the specified Element. The Element must contain
a list of item elements.

@param listElement the element containing a list of items.
@param notify true if a provicy list modified event will be triggered.
xmppserver/src/main/java/org/jivesoftware/openfire/privacy/PrivacyList.java