1. Let's say that we want our session to be for one minute. To make this happen, we will ad a ServletWebServerFactory bean to our WebConfiguration class with the following content:

@Bean
public ServletWebServerFactory servletContainer() {    
  TomcatServletWebServerFactory tomcat = 
         new TomcatServletWebServerFactory();
  tomcat.getSession().setTimeout(Duration.ofMinutes(1));
  return tomcat;
}

2. Just for the purpose of demonstration, we will get the session from the request to force its creation. To do this, we will add a new request mapping to our BookController class with the following content:

@RequestMapping(value = "/session", method = 
   RequestMethod.GET) 
public String getSessionId(HttpServletRequest request) { 
  return request.getSession().getId(); 
} 

3. Start the application by running ./gradlew clean bootRun.
4. Let's open http://localhost:8080/books/session in the browser to see the following results:

If we wait for more than a minute and then reload this page, the session ID will change to a different one.