public class InterstitialAd

A full screen interstitial ad shown at natural break points such as between game levels or activities.

InterstitialAd ad = new InterstitialAd("ca-app-pub-xxx/yyy");
ad.setAdListener(new AdListener() {
    public void onDismissed() { ad.load(); } // preload the next one
});
ad.load();

// later, at a natural break such as the end of a level
if (ad.isLoaded()) {
    ad.show();
}

Show the ad at the break you chose rather than from onLoaded(). Because onDismissed() loads the next ad, a show() inside onLoaded() makes each dismissal open another ad and the user cannot get out of the sequence.

All callbacks are delivered on the EDT. You can also let Codename One show an interstitial automatically on screen transitions with AdManager.bindInterstitialOnTransition(InterstitialAd, int).