Java 8: Three ways to calculate days between two dates

import java.time.Duration;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;

public class DateTest101 {

    public static void main(String[] args){
        String dt2 = "2017335";
        String dt1 = "2016335";
     
        DateTimeFormatter pattern = DateTimeFormatter.ofPattern("yyyyDDD");
        LocalDate dat2 = LocalDate.parse(dt2, pattern);
        LocalDate dat1 = LocalDate.parse(dt1, pattern);
        System.out.println("dat2: "+dat2.toString()+", dat1: "+dat1);
     
        //Method 1
        long daysBetween1 = dat1.until(dat2, ChronoUnit.DAYS);
        System.out.println("daysBetween1: "+ daysBetween1);
     
        //Method 2
        long daysBetween2 = ChronoUnit.DAYS.between(dat1, dat2);
        System.out.println("daysBetween2: "+ daysBetween2);
     
        //Method 3
        long daysBetween3 = Duration.between(dat1.atStartOfDay(), dat2.atStartOfDay()).toDays();
        System.out.println("daysBetween3: "+ daysBetween3);
    }
}

Reference:

1. Calculate days between two dates in Java 8

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