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Re: clear user session

Shyama Gavulla

2003-06-06



--

Hi,
Thanks for the reply. As you have said I was trying to make changes while
iterating over the loop. I cant do session.invalidate as I want the session
to be valid but certain keys to be removed. I am using tomcat 4.1 and the
same code in Jrun works fine . No errors. I wonder how that works fine.
Anyways I have a fix for that . I am trying to implement it . Thanks a lot

Shyam
----- Original Message -----
From: "Tim Funk" <funkman@(protected)>
To: "Tomcat Users List" <tomcat-user@(protected)>
Sent: Friday, June 06, 2003 3:19 PM
Subject: Re: Clear User Session


> Depending on who you talk to its a bug or not a bug in tomcat.
>
> session.getAttributeNames() returns an Enumeration. Under the covers, the
> Enumeration is actually a facade around an Iterator. Iterators are
fail-fast
> so if you are enumerating through session attributes and make changes, you
> get the error as you have described.
>
> The arguement is: is Enumeration allowed to be fail-fast?
>
> In the meantime, 4.1 and 5 were patched to not make the Enumerator
> originating from session.getAttributeNames be fail-fast.
>
>
> As an aside - if you need to clear out a session: session.invalidate() is
> much easier.
>
> -Tim
>
> Shyama Gavulla wrote:
> > Hi All,
> >
> > I just moved my webapp from jrun to tomcat. I have a method which
clears the
> > user session. The code snippet is
> >
> > Enumeration session_var = session.getAttributeNames();
> >
> >    while(session_var.hasMoreElements())
> >    {
> >       String key=(String)session_var.nextElement();
> >
> > I am getting an error here and the exception is
> >
> > java.util.ConcurrentModificationException at
> > java.util.HashMap$HashIterator.nextEntry
> >
> > How can I resolve this error.
> >
> > Thanks a lot in advance
> > shyam
>
>
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