@Override
    public void setSettings(AppSettings settings) {
        this.settings.copyFrom(settings);
        frameRate = settings.getFrameRate();
        if (frameRate <= 0) frameRate = 60; // use default update rate.
    }
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