자바 FX 아시는분 도와주세요

package application;
 
import java.awt.TextField;
 
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.PasswordField;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
 
public class Main extends Application {
	@Override
	public void start(Stage stage) {
		try {
			Label label1 = new Label("학번: ");
			Label label2 = new Label("비밀번호: ");
			TextField tfname= new TextField();
			PasswordField tfPassword = new PasswordField();
 
 
 
			grid.addRow(0, label1,tfname);
			grid.addRow(1, label2, tfPassword);
			grid.setAlignment(Pos.CENTER);
 
 
				pane.getChildren().add(grid);
 
				stage.setScene(scene);
				stage.show();
 
 
		} catch(Exception e) {
			e.printStackTrace();
		}
 
 
 
	}
	GridPane grid = new GridPane();
	StackPane pane = new StackPane();
 
	Scene scene = new Scene (pane,1280,700);
 
	public static void main(String[] args) {
		launch(args);
	}
}