IsAfter Usage of Local Date Time In JAVA

Question

I am facing the issue with localDateTime in JAVA.

I am using the isAfter function to compare the two date time but only returns correct value if there was a variation in time but not the date.

Program:

import java.time.LocalDateTime;

public class LocalDatTimeVerificaiton {

    public static void main(String[] args) throws Exception {

        LocalDateTime dateTime=LocalDateTime.now();
        System.out.println(dateTime);
        Thread.sleep(10000);
        LocalDateTime dateTime1=LocalDateTime.now();
        System.out.println(dateTime1);
        if(dateTime1.isAfter(dateTime)){
            System.out.println(dateTime+" After "+dateTime1);
        }

        if(dateTime1.isAfter(dateTime)){
            System.out.println(dateTime1+" After "+dateTime);
        }else{
            System.out.println(dateTime1+" Not After "+dateTime);
        }

    }
}

Output Actual

2017-08-11T18:32:00.466
2017-08-11T18:32:10.467
2017-08-11T18:32:00.466 After 2017-08-11T18:32:10.467
2017-08-11T18:32:10.467 After 2017-08-11T18:32:00.466

Expected

2017-08-11T18:32:00.466
2017-08-11T18:32:10.467
2017-08-11T18:32:00.466 After 2017-08-11T18:32:10.467
2017-08-11T18:32:10.467 Not After 2017-08-11T18:32:00.466

Is this the expected behavior or is am I missing something?

Answer 1

Why do you expect 18:32:10 to be before 18:32:00?

You may be misled by a typo in your code:

if (dateTime1.isAfter(dateTime)) {
  System.out.println(dateTime + " After " + dateTime1);
                            ^^^                   ^^^
}

Should probably be:

if (dateTime1.isAfter(dateTime)) {
  System.out.println(dateTime1 + " After " + dateTime);
                            ^^^                    ^^^
}