I bought Spring Pro book two years ago and plan to read it now. I found out that Spring Pro 2 was already published this year. Could somebody tell me which chapters are obsolete in Spring Pro or I should buy Spring Pro 2? Any link talking about the difference between the two versions of the frameworks?
I speculate that you mean "Pro Spring" and "Pro Spring 2.5". If so, the first is based on spring 1.2, while the second is based on spring 2.5. A lot have changed between those two versions, but the main concept is the same. If you just need to know the concepts, just read the book that you have, and go for the spring documentation and reference guide. If you need a lot of in depth knowledge of spring, go for the new version, the reference guide and spring in action.