How to destroy the Object of a SessionScoped bean

[Dushyant Agarwal]

Hi,
I have been building an application that requires me to Keep exactly one session scoped bean. But I also have another war file to be navigated to
at the end of this application. I want to destroy the Session Scoped Bean's object at the time of navigation to the second war file(i.e. clear up the memory allocated to the session scoped object ).

How can I do this ???

Would System.gc() help???

I have doubts because System.gc() doesn't guarantee garbage collection upon calling the method!!!

[Remko Strating]

If you don't need the session you could do session.invalidate() which also removes all objects from a session

I you only want the remove the attribute you could use the removeAttribute method of the session


HttpSession

[Dushyant Agarwal]

Hi,
Thanks for the reply!
But I have got a managed bean whose managed bean scope is session.
Whtaever you have suggested would have been appropriate if I had been using

HttpSession ref=(HttpSession)FacesContext.getCurrentInstance().getExternalContext().getSession();

ref.setAttribute("Key1",Value1);

However, I am declaring a variable "var" in the class (let us say )SessionBean1. Beecause of session scope the value of var will persist across the session. That will serve the same purpose as

HttpSession ref=(HttpSession)FacesContext.getCurrentInstance().getExternalContext().getSession();

ref.setAttribute("Key1",Value1);

However I am wanting to know how could I be able to destroy the Object of SessionBean1, to free the allocated memory.

[zel branco]

Try:
FacesContext context = FacesContext.getCurrentInstance();
context.getExternalContext().getSessionMap().remove("#{vtBbBean}");

[Dushyant Agarwal]

Hi,Thanks for the reply!

However it is not working.

See after I got your reply, I tried the following:
I built a class SessionBean1 as following:

public class Sessionbean1{
private str="testing for session destroy";

//gettter and setter of str
}

In the faces-Config I had set the scope of the above class
as session.

Now in the backing bean of a page Page1.jsp that conatins
a h:commandButton I placed he following code in the action method of the
commandbutton

public String button1Action(){
FacesContext.getCurrentInstance().getExternalContext().getSessionMap().remove("SessionBean1");
System.out.println(<obj>.getStr()); //here obj retreives the
//session scoped object of
//SesionBean1 class.
}


Probably this code should have given a nullPointer Exception because

FacesContext.getCurrentInstance().getExternalContext().getSessionMap().remove("SessionBean1");

should have destroyed the object of SessionBean1.But it did not.

My problem still stands .Please help!!
[ January 07, 2008: Message edited by: Dushyant Agarwal ]

[Richard Green]

However it is not working.

Did you try it with "#{SessionBean1}"?

context.getExternalContext().getSessionMap().remove("#{SessionBean1}");

[ January 08, 2008: Message edited by: Richard Green ]

[Dushyant Agarwal]

Hi,
Thanks for reply .
I finally got to get it working with "SessionBean1".
But I wanted to know whether after we execute

context.getExternalContext().getSessionMap().remove("SessionBean1");

if we try to access the reference of Session scoped bean then should we get null as a result or a new reference of the same bean. I am getting a new reference of the Session scoped bean in that case.