Cannot extend session timeout on Web Logic Server

I have a Spring controller method as such:

@RequestMapping(value = "/resetTimeoutForClient",  method = 
    {RequestMethod.POST, RequestMethod.GET}, produces = "application/json")
    public ResponseEntity<String>  resetTime(HttpServletRequest request) {

        HttpSession session = request.getSession(false);
        Date date = java.util.Calendar.getInstance().getTime();
        DateFormat formatter = 
        DateFormat.getDateTimeInstance(DateFormat.MEDIUM,DateFormat.MEDIUM);
        JsonObject jsonObjectReturn = new JsonObject();
        jsonObjectReturn.addProperty("checkingSessionAt", date.toString());

        if (null == session){
            jsonObjectReturn.addProperty("sessionIsActive", false);
        }
        else {
            int sessMax = session.getMaxInactiveInterval();
            Date lastAccessed = new Date(session.getLastAccessedTime());
            String lastAccessedReadable = formatter.format(lastAccessed);
            String theSessionID = session.getId();
            jsonObjectReturn.addProperty("sessionID", session.getId());
            jsonObjectReturn.addProperty("sessionIsActive", true);
        }

        String testme = jsonObjectReturn.toString();
        return new ResponseEntity<>(testme, HttpStatus.OK);
}

The purpose of this method is that, once called via an AJAX call (see next), the container (Oracle Web Logic) would reset the session timeout, which is set to 45 minutes in the web.xml file.

The AJAX call is in a function and looks like:

function sessPingServer() {
    return $.ajax({
        url: "/mydomain/resetTimeoutForClient",
        type: 'GET'
    });
}   

... and this AJAX function is called by:

sessPingServer()
    .done(function (response) {
    if (!response.sessionIsActive){
        // Log em out...
        sessLogOut();
    }
    else {
        // Restart timers...
    }
})

When a button on a modal that is to "Extend the Session" is clicked, the AJAX code would run and call that server method.

So I have a simple question. From what I have been reading on several SO pages, I thought that having this AJAX code calling the controller method would reset the session timeout timer. It does not. I have breakpoints set up in the controller method and can verify that the session ID is the same each time that method is called, and the session lastAccessed values are correct.

Can some smart people please tell me what I am doing wrong here? Why does this construct not reset the session timer? Is there some very obvious piece that I am missing?

Thank you