@Override
    public void simpleInitApp() {
        /* This blue box is our player character. */
        Box b = new Box(1, 1, 1);
        player = new Geometry("blue cube", b);
        Material mat = new Material(assetManager,
          "Common/MatDefs/Misc/Unshaded.j3md");
        mat.setColor("Color", ColorRGBA.Blue);
        player.setMaterial(mat);
        rootNode.attachChild(player);
    }
Sample 4 - how to trigger repeating actions from the main event loop.
In this example, you use the loop to make the player character 
rotate continuously.
jme3-examples/src/main/java/jme3test/helloworld/HelloLoop.java