Returns the maximum time interval, in seconds, that the servlet container will keep this session open between
client accesses. After this interval, the servlet container will invalidate the session. The maximum time
interval can be set with the setMaxInactiveInterval method. A negative time indicates the session should never
Re-stores dirty objects back into the session. This is necessary to support clustering, because (in most
application servers) session objects are only broadcast around the cluster from setAttribute(). If a mutable
session object is read and changed, those changes will be limited to a single server in the cluster, which can
cause confusing application failures in the event of a failover. Does nothing if there are no changes, or
the session has been invalidated.