This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Well, how about right here, the Cattle Drive? You write code assignments, you send them in to be "nitpicked", you get feedback on what you wrote, then you tweek the code some more and the cycle continues - at the end you have a really good understanding of what you're learning.
There are others of course, but, well, they can't compare with the unique experience that you get from doing the Cattle Drive assignments, with someone looking over your code and giving you feedback until it's more than just code that works.
If the Cattle Drive isn't your choice, or if you're looking for additional resources while doing the Cattle Drive, dickbaldwin.com has some tutorials on advanced java topics.