How to write and save this coding program as a java file like Project.java

import javax.swing.*;

public class LeapYear { JFrame f; int dialog(){ f=new JFrame(); int yr=Integer.parseInt(JOptionPane.showInputDialog(f,"Enter a year ")); return yr; } void leapYearFind(int y){ if((y % 400 == 0) || ((y % 4 == 0) && (y % 100 != 0))) System.out.println("Year " + y + " is a leap year"); else System.out.println("Year " + y + " is not a leap year"); }

public static void main(String[] args) { LeapYear leapYear = new LeapYear(); while(true){ int year =leapYear.dialog(); if(year == -99){ System.out.println("Program is exited"); System.exit(0); }else{ leapYear.leapYearFind(year); } } } }