title: What's the best way to switch between scenes in JavaFX?
body: <p>I'm developing a menu using plain <code>JavaFX</code> (no CSS or FXML) but I can't figure out a good way to switch between scenes. </p>
  
  <p>I want to have a fixed <code>primaryStage</code> whose content I can change. </p>
  
  <p>I have a class for everything in the menu (New Game, Options, Info and Exit). If I create a <code>start()</code> method for every class my program it doesn't work, but i also wouldn't like to create a new stage for everything.</p>
  
  <p>How can I fix this?</p>