Oh, yeah, Babji, there are lots of changes. For one thing, v6 is using
Java 1.4 and can use 1.5; the highest v5 goes is 1.3 (on its own -- I know you can set it to use 1.4, but you're asking for a world of trouble). Many of the methods have been deprecated, such as Enumeration. It doesn't hurt anything and your processes will still work just fine; it just means that you're being warned that you need to make changes because eventually, those methods will go away and you will go from warnings to flat-out errors. And the reason the methods are going away is because the replacement methods are much better in one fashion or another (speed, efficiency, threading, etc.).
Also, you can go to the "deprecated" lists for classes in the API documentation and they will tell you what the replacement is. If the entire class or package has been deprecated, Websphere usually tells you what replaced it. At least, I think that's correct. I'm taking three classes right now on top of having to learn
Struts "yesterday", so my brain is dribbling gray matter. I'm sure someone will correct me if I'm wrong. Just be nice, guys.