A pretty light video at Javalobby (login required) of Knut Risvik telling about the Google infrastructure and how they use Java for a lot of their stuff. A good watch if you do not already know stuff about GFS and MapReduce, if you do there is not much news in there.
About their Java use: Adwords and GMail use a lot of Java, they use lots of JNI to talk to the low level Google systems, they are friendly with Sun and they employ a lot of very high profile Java people.
