title: How to open two Javafx windows?
body: <p>I'm using javafx, want to write a code in 'setOnAction' of a button to close a javafx1 class an run javafx2 class, but i've seen error 'Application launch must not be called more than once'. How can i fix this?</p>
  
  <pre><code>//This code is in the class JavaFX1:
  button.setOnAction(new EventHandler&lt;ActionEvent&gt;() {
        @Override
        public void handle(ActionEvent event) {
            JavaFX2.main(null); //How can i change current line?
            stage.close();
        }
  });
  </code></pre>