@Override
    public void run() {
        initInThread();

        do {
            listener.update();

            if (frameRate > 0) {
                sync(frameRate);
            }
        } while (!needClose.get());

        deinitInThread();

        logger.fine("NullContext destroyed.");
    }
Accesses the listener that receives events related to this context.

@return the pre-existing instance
jme3-core/src/main/java/com/jme3/system/NullContext.java