gistfile1.java

private ApplicationContext getApplicationContext(HttpSessionEvent event){
  ServletContext servletContext = event.getSession().getServletContext();
  ApplicationContext context = (ApplicationContext) servletContext.getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
  return context;
}

public void sessionCreated(HttpSessionEvent event) {
  TestService testService = (TestService) getApplicationContext(event).getBean("testService");
  //....
}