@Override
    public void onDestroy() {
        logger.fine("onDestroy");
        if (app != null) {
            app.stop(false);
        }
        app = null;
        super.onDestroy();
    }
Called by the system when the application is being destroyed.  In this case,
the jME application is actually closed as well.  This method is not called
during device configuration changes or when the application is put in the
background.
jme3-android/src/main/java/com/jme3/app/AndroidHarnessFragment.java