system = FALLBACK_DEFAULT_SYSTEM;
system = new LWJGLSystemProvider();
    public static DisplaySystem getDisplaySystem(String key) {        // force to initialize joystick input before display system as there are        // lwjgl issues with creating it afterwards        JoystickInput.get();        system = getCachedSystemProvider(key);        if (system == null) {            // if none defined by Service.providers, use fallback default            system = FALLBACK_DEFAULT_SYSTEM;        }        return getDisplaySystem();    }