No it won't improve performance. Why would you think it would? All that happens when you implement Serializable (which, remember is a "Tag" interface that does not define any methods) is that that object can now be Serialized to a Stream or File by the Java object Serialization framework. That is useful (for instance) if you are using Session clustering of any sort, since session clustering mechanisms either (a) Serialize things to a stream to send them from one machine to another or (b) Serialize them into a Binary Large Object column in a database so it can be shared among multiple application servers. So, while making your objects stored in your sessions serializable won't improve performance, it *may* improve the scaleability of your app, which is a related matter. However, you must remember that things like back-end connections CANNOT be serialized at all. They must remain transient. So if you have a lot of set-up data, or some cached data from the back end, this may help, but if you don't then it won't even help scaleability.
Kyle [ April 20, 2002: Message edited by: Kyle Brown ]