JOPtionPane.showInputDialog（）的各个参数详解，为什么我的这个小程序不对 ...

import javax.swing.*;
public class Class3
{
    public static void main(String[] args)
    {
        int num1=(int)(System.currentTimeMillis()%10);
        int num2=(int)(System.currentTimeMillis()*7%10);
        int num3=(int)(System.currentTimeMillis()*3%10);
        String answer = JOPtionPane.showInputDialog("what is "+num1+"+"+num2+"+"num3+"?");
        int answerInt =Integer.parseInt(answer);
        JOPtionPane.showMessageDialog(null,num1+"+"+num2+"+"+num3+"="+answerInt+"is"
        (num1+num2+num3==answerInt));
    }
}