code: public void setDisplay(int display) {
      if (!Platform.getCurrent().is(LINUX)) {
        throw new UnsupportedOperationException("Unsupported platform: " + Platform.getCurrent());
      }
  
      options.get(DISPLAY).setValue(display);
    }
docs: Sets the X display to use.  Only works on GNU/Linux.  Typically this allows you to open Opera
  in an X virtual framebuffer.
  
  @param display the X display to use
  @throws UnsupportedOperationException if on a non-GNU/Linux operating system