Are you sure you REALLY want to run multiple istances of your server???
I suspect that you want to serve more than one client...this means that anytime a client connects to the server, the server creates a workerThread able to handle the communication with the client and then the server gets back to the waiting state (while the worker thread keeps serving the client)...and so on...
I think you misunderstood the book: the key is that you can be in the same session for 2 different requests, as long as the requests come from the SAME client (browser), this is the definition of session!
If the 2 requests come from different clients (different browsers), then each client (browser) needs to have its own session, though 2 different requests coming from 2 different clients (browsers) cannot be in the same session.
If you want to study seriously, you shouldn't care that much about "which one is easier".
Still, in the industry it will take a long long time before you have/can write code using Java 1.5...
I develop in Java in a leading edge technology company, and the JVM is Java 1.1 compliant...ok this might not be the "rule" but it does happen, if you want to take is slow, then go for the SCJP 1.4, when you feel comfortable with Java 1.5 you can always take the update from SCJP 1.4 to SCJP 1.5 (without paying the whole fee), if you want to do it faster, then study for the SCJP 1.5...if you don't care about Java 1.5, then simply go for SCJP 1.4.
Trust me...a bunch of Project Managers have no idea about generics and stuff...and most likely you will have to develop on JVM 1.2/1.4.
Gio :-) [ July 22, 2006: Message edited by: Barry Gaunt ]
I agree with the previous poster, if you have been doing Java programming for the last 2 years, then go for the SCJP, after that (or before, it does not matter), if you want to have a broad knowledge of some other branches of Java, then take the SCJA.