LinkedIn is 99% Java but 100% Mac
From the LinkedIn blog here.
Ahh so thats why your site is so shockingly slow, has lots of logging out problems (I’m guessing overly cautious cookie issues) and is a dog to navigate. The mac thing is cool and all that (I love the way they spend a fortune on a laptop, very overpowered desktop (drop the java guys and you will save yourself some money on hardware) and then give their developers two reams of paper to hold up their monitors)