Java socket bridge

So I'm trying to create a socket bridge in Java to allow me to use actual sockets in Javascript. It works like this:
I include the applet where I want to use sockets, get a reference to it with Javascript, and then I can call applet code by using ref.code.

The applet must be signed and given permission so it can make connections to any domain. Only the main thread has these permissions. You also can't call the socket functions directly from Javascript.

My question is if I start a thread from the main thread will it have the same permissions as the main thread? Is it possible to call code from a thread and have that code run in the thread?

Imagine the cool software we could create if this existed. Obviously we can already do so with Java but nobody wants to touch it.