Java EE (Java Enterprise Edition) General Discussion

I have a jsp page with a table which contains data from a database.
From this page I open a popup window that permits to update these informations.
So from popup window (also jsp page) I submit a servlet and before closing it with wondow.close(), I try to update opener window with:

window.opener.location.reload();

but it sometimes works and sometimes not.
Is there any explanation of this?
Thanks in advance.