@Override
    public void initialize(){
        super.initialize();

        System.out.println("Initialize");

        // create a box
        boxGeom = new Geometry("Box", new Box(2, 2, 2));

        // load some default material
        boxGeom.setMaterial(assetManager.loadMaterial("Interface/Logo/Logo.j3m"));

        // attach box to display in primary viewport
        viewPort.attachScene(boxGeom);
    }
Test a bare-bones application, without SimpleApplication.
jme3-examples/src/main/java/jme3test/app/TestBareBonesApp.java