One of the best parts of my job is going on customer visits. Yesterday I got to visit the folks that run HBO&Cinemax. No, not the CEO and a pile of executives: the folks who make the bits flow. The server and storage farms, the transcoding arrays, the video stream construction and the satellite uplinks. It's all in an impressive 5 9's reliability site on Long Island. Redundant everything. Big power supplies. There are big bags of Java code in the control system. I had a great time with the engineers who designed, built and run the whole thing. One of the pieces was the app that schedules and manages the movement and assembly of assets (movies, commercials, whatever...) from the storage arrays to the satellite streamers. It's really the central crossbar that gets everything to the right place at the right time. The hard part is doing that and dealing with all of the failure scenarios - including the failure of itself.
A few weeks ago I got to visit a bunch of engineers at Sabre - the folks behind travelocity and a whole lot of the IT infrastructure of modern civil aviation. One of the fellows I talked to was involved in the piece of software that decides where to put containers that are loaded into aircraft: balancing the load so that the planes don't fall out of the sky. Mission critical everything. They're a huge Java shop.
And before that it was FedEx - more Java engineers than Sun... The Weather Channel... Home Depot... Delta airlines... Equifax... Cingular...
There are so many ways that Java apps touch peoples lives every day. And they aren't even aware of it. The web is just the tip of the iceberg.