Cannot create a session after the response has been committed

Question

Opening the JSF page gives me the following exception:

Caused by: java.lang.IllegalStateException: Cannot create a session after the response has been

Answer 1

The reason is that:

1. JSF stores the page component structure in HttpSession
2. If the page content is very large and the session has not been previously created, some response may have been written and the error above happens

So the solution is to create the session before the Facelet (/JSP) page is printed. An crude example could be like:

@PostConstruct
void initialiseSession() {
    FacesContext.getCurrentInstance().getExternalContext().getSession(true);
}

/napu