I'm taking over a colleague's GWT project soon and I've never coded in it before. However as I come from a Java background, I'm sure I won't be banging my head too much or be too overwhelmed when I open Eclipse!
What would be the best book to pick up, or tutorial to go through?
What particular packages / tricks do you recommend I look at first?
Do you wish you had of known about something when you first started in it?
EDIT:
The original code is written in 1.4. I'll be updating it to 1.7, among other things. Which leads me to an additional question: Is there any significant updates I should pay particular attention to?