GMail, Google Calendar, AdSense, AdWords, Android to name a few of the _actual_ heavy hitters from Google. Sure, not the majority, but they are all the bigger ones.

http://google-opensource.blogspot.ca/2009/01/opengse-release...

(I think Google Sites is also written in Java).

Amazon is pretty much a big Java shop (don't forget the companies they acquired as well). Check out their jobs site.