Predictably Steve Jobs thinks otherwise: “Java’s not worth building in. Nobody uses Java anymore. It’s this big heavyweight ball and chain”. So iPhone apps will use Objective C, a fairly disgusting and overcomplicated and unconcise language in my humble opinion.
Click for full-size image.
Sunspider provides some really in-depth information which may be of interest (my computer is called ‘BTComp’ and time to run in ms is in [square brackets]):
BTComp FF 3.1 Portable + Tracemonkey [2,506]
BTComp FF 3.1 Portable [4,346]
BTComp FF 3.04 + Plugins [4,966]
BTComp IE 7 [42,283]
School FF 3.0.3 [2,561]
School Safari 3.1.2 [3,059]
School IE 7.0.5730.13 [23,382]