如何让代码显示在 jframe 中？

如何解决如何让代码显示在 jframe 中？

当 jframe 为空时，代码显示在终端中，请帮忙。我不想更改整个代码。如果有人可以提供帮助，请快速回复。如果有比 jframe 更好的选择，请告诉我。 the error as a picture

（忽略这部分只是为了完成字数限制）

package calculator;
import java.awt.Color;
import java.util.Scanner;
import javax.swing.ImageIcon;
import javax.swing.JFrame;

public class project {

    public static void main(String[] args) {

        JFrame frame = new JFrame("calculator");
        frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        frame.setSize(700,600);
        frame.setResizable(false);
        frame.getContentPane().setBackground(Color.cyan);

        ImageIcon image = new ImageIcon("calculator_logo");
        frame.setIconImage(image.getimage());

        Scanner input = new Scanner( system.in );

        System.out.printf("%s \n %s \n %s \n %s \n","choose any option or press q to exit:","1) add","2) multiply","3) divide");

        String choice = input.nextLine();

        int number1; //first number to add
        int number2; //seconed number to add
        int answer; // answer

        if(choice.equals("1")) {

            System.out.print("Enter first number: ");
        number1 = input.nextInt();//read1
        System.out.print("Enter seconed number: ");
        number2 = input.nextInt();//read 2
        answer = number1 + number2; //add numbers
        System.out.printf("answer is %d\n",answer);//display sum

        } else if(choice.equals("2")) {

            System.out.print("Enter first number: ");
        number1 = input.nextInt();//read1
        System.out.print("Enter seconed number: ");
        number2 = input.nextInt();//read 2
        answer = number1 * number2; //add numbers
        System.out.printf("answer is %d\n",answer);//display sum

        } else if(choice.equals("3")) {

            System.out.print("Enter first number: ");
        number1 = input.nextInt();//read1
        System.out.print("Enter seconed number: ");
        number2 = input.nextInt();//read 2
        answer = number1 / number2; //add numbers
        System.out.printf("answer is %d\n",answer);//display sum

        } else if(choice.equalsIgnoreCase("q")) {
            System.out.println("the app will close Now!");
            System.exit(0);
        }

    }// end of method main

} // end of class project