1. There are things called db_links.
Here is a link to some examples of using and creating database links. If on that page you scroll up a little bit you will see the CREATE DATABASE LINK command syntax.
(I just couldn't find a good anchor number to use to get you to this part of the page.)
2. No special rights than normal.
3. Not quite sure what youa re asking here, but you could always created stored procedures that would handle this, if you can't directly in Java.
I haven't heard of the ability to create updatable views from java code, but I am not completely experienced enough in that area of Oracle to know if there is.
Hope that helps
Mark