session invalidates after replacing the bean class

[Eqbal]

I am using session that never expires (using the
session.setMaxInactiveInterval(-1) method). I have a bean on a JSP
page that has session scope that remains in session properly. But when
I replace the jar file containing the bean class my session seems to
get invalidated. Is there any way to avoid this? I am using WAS 4.0.5.

Any help/suggestions are appreciated.

Thanks.