Dunno either! But you should start your search here methinks:
https://JogAmp.org/deployment/jogamp-next/javadoc/jogl/javadoc/com/jogamp/newt/Window.html
import com.jogamp.newt.Window;
Window window;
void setup() {
size(800, 600, P2D);
window = (Window) getSurface().getNative();
println(window);
}