No. The re-compilation starts at a JS applet from where all relevant Java classes have to be re-compiled.
No. It only re-compiles JS applets that extend js.JsApplet.
A JS applet is a Java applet that extends js.JsApplet and conforms to the JScripter specifications.
A JS applet, that properly uses JS Standard Library and only the Java standard classes that have been emulated by JS Emulation Library, normally conforms to the JScripter specifications.
JRecompiler will end up with exceptions.
Not at all.