Changing object for vuforia integrate JPCT-ae

Question

I had successfully integrate vuforia with jpct-ae. Now, I want to change the cube into other object (either obj or md2 file). Below is my code in ImageTargetRenderer.java (not sure is true or not). How can I call this object to render on a marker?

public void banana()
{
    world = new World();
    world.setAmbientLight(20, 20, 20);

    sun = new Light(world);
    sun.setIntensity(250, 250, 250);
    mngr = mActivity.getAssets();
    try {
        objStream = mngr.open("bananatree.obj");
        } catch (IOException e) {
            e.printStackTrace();
        }
    try {
        mtlStream = mngr.open("bananatree.mtl");
        } catch (IOException e) {
            e.printStackTrace();
        }

    model = Loader.loadOBJ(objStream, mtlStream, 1);
}