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.
The Web site has the same documentation that comes with the SDK, including a developer guide and API reference. Those are fairly decent for a project of this scope, though they are certainly not complete. They are, however, everything there is, from an official source.