nope but you can leave it free floating and it'll grow. But if java moss grows free floating it tends to look a bit stringy. You can sandwich the moss in between a mesh and it'll grow that way and start a little floor cover in the area.
Yes, just spread it thin through out the area you want to grow on and it'll take off, but it takes a while. Like a month to see growth, but its cool. Just remember to tie it down with something that won't end up melting away. I personally just use fishing string to tie things down.
Or, you if you want you can go to walmart or something and get a nylon net material and, spread it over a rock or what ever you want, and wrap it with that nylon net and tie the end of it. I've done this to rocks, it looks pretty neat like a little bush actually. But like I said, it'll take sometime to see growth, but its a fun experiment.