[dekz]

I believe the Java is simply for the Fonts which falls back to Flash if you say no.

User Agent provides quite a lot of identifying information; OS/OS version, browser version. Panopticlick breaks this down for you, one in every 186,062 data points they have has my User Agent. This provides 17.5 bits of identifying entropy (log2 of 186062).

They mention they have a total database size of 2,046,684, which requires 20.96 bits of identifying information. So to answer your question about how much identifying information you can get from Javascript, a lot.

You can then also get Flash Version, Time Zones, Browser Plugins, IP Address, Screen Info.