Hi
Data Structures and Algorithsm in
Java by Robert Lafore (Mitchell Waite Series)
ISBN: 1571690956. My fav by far. Very easy to read and understand the concepts.
I also use DataStructures, Algorithms and appllications in Java by Sartaj Sahni (McGraw Hill Publications) ISBN: 0072519096
The Sahni book is much harder to 'grasp' but it's a lot more complete. What I do it read the concept in the Mitchell Waite series and then if I need more details I read it in this book.
Great books, I use them extensively as teaching aides/references.
Hope this helps.