code: public void sessionAttributeRemoved(ISession session, Object name, Object value, Boolean oldIsBindingListener) {
          HttpSessionAttributeListener listener = null;
          HttpSessionBindingEvent event = null;
          HttpSession httpsession = (HttpSession) _adapter.adapt(session);
  
          event = new HttpSessionBindingEvent(httpsession, (String) name, value);
          if (value instanceof HttpSessionBindingListener) {
              if (oldIsBindingListener.booleanValue()) {
                  ((HttpSessionBindingListener) value).valueUnbound(event);
              }
          }
      }
docs: Method sessionAttributeRemoved
  <p>
  
  @see com.ibm.wsspi.session.ISessionStateObserver#sessionAttributeRemoved(com.ibm.wsspi.session.ISession, java.lang.Object, java.lang.Object)