This Java application uses a switch node to swap between two shapes. The switch is driven by two AWT buttons.

 import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Frame;
import java.awt.Panel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.media.j3d.Appearance;
import javax.media.j3d.BoundingSphere;
import javax.media.j3d.BranchGroup;
import javax.media.j3d.Canvas3D;
import javax.media.j3d.DirectionalLight;
import javax.media.j3d.Locale;
import javax.media.j3d.Material;
import javax.media.j3d.Node;
import javax.media.j3d.PhysicalBody;
import javax.media.j3d.PhysicalEnvironment;
import javax.media.j3d.Switch;
import javax.media.j3d.Transform3D;
import javax.media.j3d.TransformGroup;
import javax.media.j3d.View;
import javax.media.j3d.ViewPlatform;
import javax.media.j3d.VirtualUniverse;
import javax.vecmath.AxisAngle4d;
import javax.vecmath.Color3f;
import javax.vecmath.Point3d;
import javax.vecmath.Vector3f;

import com.sun.j3d.utils.geometry.Box;
import com.sun.j3d.utils.geometry.Cone;

/**
 * This application uses a switch node to swap between two shapes. The switch is
 * driven by two AWT buttons.
 * 
 * @author I.J.Palmer
 * @version 1.0
 */
public class SimpleSwitch extends Frame implements ActionListener {
  protected Canvas3D myCanvas3D = new Canvas3D(null);

  /** The exit button */
  protected Button exitButton = new Button("Exit");

  /** Set the shape to a box */
  protected Button boxButton = new Button("Box");

  /** Set the shape to a cone */
  protected Button coneButton = new Button("Cone");

  /** The switch that is used to swap between the shapes */
  protected Switch firstSwitch = new Switch(0);

  /**
   * This function builds the view branch of the scene graph. It creates a
   * branch group and then creates the necessary view elements to give a
   * useful view of our content.
   * 
   * @param c
   *            Canvas3D that will display the view
   * @return BranchGroup that is the root of the view elements
   */
  protected BranchGroup buildViewBranch(Canvas3D c) {
    BranchGroup viewBranch = new BranchGroup();
    Transform3D viewXfm = new Transform3D();
    viewXfm.set(new Vector3f(0.0f, 0.0f, 10.0f));
    TransformGroup viewXfmGroup = new TransformGroup(viewXfm);
    ViewPlatform myViewPlatform = new ViewPlatform();
    PhysicalBody myBody = new PhysicalBody();
    PhysicalEnvironment myEnvironment = new PhysicalEnvironment();
    viewXfmGroup.addChild(myViewPlatform);
    viewBranch.addChild(viewXfmGroup);
    View myView = new View();
    myView.addCanvas3D(c);
    myView.attachViewPlatform(myViewPlatform);
    myView.setPhysicalBody(myBody);
    myView.setPhysicalEnvironment(myEnvironment);
    return viewBranch;
  }

  /**
   * Add some lights so that we can illuminate the scene. This adds one
   * ambient light to bring up the overall lighting level and one directional
   * shape to show the shape of the objects in the scene.
   * 
   * @param b
   *            BranchGroup that the lights are to be added to.
   */
  protected void addLights(BranchGroup b) {
    BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0),
        100.0);
    Color3f lightColour1 = new Color3f(1.0f, 1.0f, 1.0f);
    Vector3f lightDir1 = new Vector3f(0.0f, -1.0f, 0.0f);
    Color3f lightColour2 = new Color3f(1.0f, 1.0f, 1.0f);
    Vector3f lightDir2 = new Vector3f(0.0f, 1.0f, 0.0f);
    DirectionalLight light1 = new DirectionalLight(lightColour1, lightDir1);
    light1.setInfluencingBounds(bounds);
    DirectionalLight light2 = new DirectionalLight(lightColour2, lightDir2);
    light2.setInfluencingBounds(bounds);
    b.addChild(light1);
    b.addChild(light2);
  }

  /**
   * This builds the content branch of our scene graph. The root of the shapes
   * supplied as a parameter is slightly tilted to reveal its 3D shape. It
   * also uses the addLights function to add some lights to the scene.
   * 
   * @param shape
   *            Node that represents the geometry for the content
   * @return BranchGroup that is the root of the content branch
   */
  protected BranchGroup buildContentBranch(Node shape) {
    BranchGroup contentBranch = new BranchGroup();
    Transform3D rotateCube = new Transform3D();
    rotateCube.set(new AxisAngle4d(1.0, 1.0, 0.0, Math.PI / 4.0));
    TransformGroup rotationGroup = new TransformGroup(rotateCube);
    contentBranch.addChild(rotationGroup);
    rotationGroup.addChild(shape);
    addLights(contentBranch);
    return contentBranch;
  }

  /**
   * This creates the shapes used in the program. A switch node is created
   * that has its write capability set so that we can swap the rendered shape.
   * Then a box and a cone are created and added to the switch.
   * 
   * @return Node that is the switch node
   */
  protected Node buildShape() {
    Appearance app = new Appearance();
    Color3f ambientColour = new Color3f(1.0f, 0.0f, 0.0f);
    Color3f emissiveColour = new Color3f(0.0f, 0.0f, 0.0f);
    Color3f specularColour = new Color3f(1.0f, 1.0f, 1.0f);
    Color3f diffuseColour = new Color3f(1.0f, 0.0f, 0.0f);
    float shininess = 20.0f;
    app.setMaterial(new Material(ambientColour, emissiveColour,
        diffuseColour, specularColour, shininess));
    //Set the capability so that we can change the switch value
    firstSwitch.setCapability(Switch.ALLOW_SWITCH_WRITE);
    //Add the two shapes to the switch
    firstSwitch.addChild(new Box(2.0f, 2.0f, 2.0f, Box.GENERATE_NORMALS,
        app));
    firstSwitch.addChild(new Cone(2.0f, 4.0f, Cone.GENERATE_NORMALS, app));
    return firstSwitch;
  }

  /**
   * Process the AWT events and perform the appropriate actions. If the exit
   * button has been pressed, quit the application, if the box button has been
   * pressed, select the box child of the switch and if its the cone button
   * select the cone child.
   * 
   * @param e
   *            ActionEvent that is to be processed.
   */
  public void actionPerformed(ActionEvent e) {
    if (e.getSource() == exitButton) {
      dispose();
      System.exit(0);
    } else if (e.getSource() == boxButton) {
      firstSwitch.setWhichChild(0);
    } else if (e.getSource() == coneButton) {
      firstSwitch.setWhichChild(1);
    }
  }

  public SimpleSwitch() {
    VirtualUniverse myUniverse = new VirtualUniverse();
    Locale myLocale = new Locale(myUniverse);
    myLocale.addBranchGraph(buildViewBranch(myCanvas3D));
    myLocale.addBranchGraph(buildContentBranch(buildShape()));
    setTitle("SimpleWorld");
    setSize(400, 400);
    setLayout(new BorderLayout());
    Panel bottom = new Panel();
    bottom.add(boxButton);
    bottom.add(coneButton);
    bottom.add(exitButton);
    add(BorderLayout.CENTER, myCanvas3D);
    add(BorderLayout.SOUTH, bottom);
    exitButton.addActionListener(this);
    boxButton.addActionListener(this);
    coneButton.addActionListener(this);
    setVisible(true);
  }

  public static void main(String[] args) {
    SimpleSwitch ss = new SimpleSwitch();
  }
}