java 소숫점 숫자 맞추기 도와주세요 ㅜㅜ

output 콘솔에 뜨는건 되는데..

JOptionPane 을 사용해서 팝업을띄우는건 안되네요 ㅜㅜ 어떻게해야할까요?

새로 변수를 만들어서 소숫점 두자리로 만들고띄워야하나요??

방법이 있다면 문법이어떻게되나요?

도와주세요

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package assignment01;

import javax.swing.JOptionPane;

/**

* @author CHOL HYUN PARK

public class Assignment01 {

public static void main(String[] args) {

double principal, rate, term, monthlyPayment;

String p,r,t, mp;

p = JOptionPane.showInputDialog("Enther Principal ");

t = JOptionPane.showInputDialog("Enter term in years ");

r = JOptionPane.showInputDialog("Enter rate in percent ");

principal = Double.parseDouble(p);

term = Double.parseDouble(t);

rate = Double.parseDouble(r);

term *= 12 ;

rate /= 1200 ;

monthlyPayment = principal*rate/(1.0-Math.pow(rate+1, -term));

System.out.print("Your monthly payment is ");

System.out.printf("%1$.2f", monthlyPayment); // setpercision 2

System.out.print(" USD ");

*/ 요건 콘솔에뜨게

//Display output

JOptionPane.showMessageDialog(null, "Your monthly payment is " + monthlyPayment + " USD ", "Results",JOptionPane.PLAIN_MESSAGE);

// 이건 팝업

}//main method

}// class Assignment01