【初学JavaFX遇到的问题。】

package application;
        
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;


public class Main extends Application {
        @Override
        public void start(Stage primaryStage) {
                try {

                        System.out.println(Math.sin(Math.PI/2));
                        BorderPane root = new BorderPane();
                        Scene scene = new Scene(root,400,400);
                        scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
                        primaryStage.setScene(scene);
                        primaryStage.show();
                } catch(Exception e) {
                        e.printStackTrace();
                }
        }
        
//        public static void main(String[] args) {
//                launch(args);
//        }
}


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1. JavaFX没有main函数为什么也能执行？
2. JavaFX的main函数args为什么要传递参数（这里并没有从终端读取的意思呀。
3. 包名非要是application吗，如果全文替换可以吗？