How to exit the application which consists of few classes?

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http://stackoverflow.com – My first class "public class MyActivity extends Activity" immediately runs another class "public class MyActivity2 extends AndroidApplication", which runs Libgdx "class MyGame". I exit MyGame class with "Gdx.app.exit()", which returns to first class. But it starts second class again... Cycle. So how to exit the application? Thanks! (HowTos)