@Override
    public void simpleUpdate(float tpf) {
        // make the player rotate:
        player.rotate(0, 2*tpf, 0); 
    }
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