WebObjects was in its prime in 2005, and ran circles around everything out there (Java or not). Even in it's completely unsupported (by Apple) state today, it probably still runs circles around most of the frameworks.
I completely agree with Paul and the others at Ycombinator. Although my writeup was specifically about control systems, my point is that this device is not about eBook reading, so comparing it to the Kindle is a waste of time.