public Map act(Redirector redirector,
    SourceResolver resolver,
    Map objectModel,
    String src,
    Parameters par) throws Exception 
{
        Request request = ObjectModelHelper.getRequest(objectModel);
        if (request != null) {
            Session session = request.getSession (false);
            if (session != null) {
                if (session.isNew()) {
                    getLogger().debug("Session is new");
                } else {
                    getLogger().debug("Session is old");
                }
            } else {
                getLogger().debug("A session object was not created");
            }
        }
        return null;
}

A simple Action that logs if the Session object has been created