Session invalidation error how to handle session in struts 6.0.0

Question

Currently I'm handling this way but session.invalidate throwing an exception

if(null==mode)
{
    HttpSession session = getServletRequest().getSession(false);
    log.debug(session + "" + getServletRequest().getSession(false));
    if (null != getSession()) {
        session.invalidate();   
    }
    session =  getServletRequest().getSession(true);
}           
userVO=(UserVO)getSessionObject(getServletRequest(),"USER_INFO");

Can anyone help me to how to handle session in struts 6.0.0 version with code snippet