I used Java in college ten years ago and not much since. Is Java SE7 so different from the second edition that I need to get a new book? Are the syntax totally different with lots of deprecated stuff?
There is always deprecated stuff and new and improved libraries, but there are also some important new concepts you need to learn I you do not know them already.
One of the biggest examples is generics.
I don't think you need a book. There are plenty of online resources for java.
The libraries have changed quite a bit, but the language is pretty much the same. The only thing I'd call a major difference is generics. Aside from that, it's mostly just bells and whistles (like enums, varargs, for-each loops).
I would buy a new book, as a couple newer classes came out since, but you should see them as depreciated, or suggestions in the javadoc to use the newer classes. I think Vector was one, and StringBuilder vs whatever the older one was, lots of other ones too.
I'd get a book they're cheap, just skim it over and look at the structure and classes and how generics work.