ChronoLocalDateTime compareTo() method in Java with Examples

The compareTo() method of ChronoLocalDateTime interface in Java method compares this date to another date.

Syntax:

default int compareTo(ChronoLocalDateTime other)

Parameter: This method accepts a parameter other which specifies the other date to compare to and it is not specifically null.

Return Value: It returns the comparator value which is negative if it is less else it is positive if it is greater.

Below programs illustrate the compareTo() method of ChronoLocalDateTime in Java:

Program 1:

// Program to illustrate the compareTo() method

import java.util.*;
import java.time.*;
import java.time.chrono.*;

public class GfG {
    public static void main(String[] args)
    {
        // First date
        ChronoLocalDateTime dt
            = LocalDateTime.parse("2018-12-06T19:21:12");

        System.out.println(dt);

        // Second date
        ChronoLocalDateTime dt1
            = LocalDateTime.parse("2018-12-06T19:21:12");

        System.out.println(dt1);

        try {
            // Compare both dates
            System.out.println(dt1.compareTo(dt));
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

2018-12-06T19:21:12
2018-12-06T19:21:12
0

Program 2:

// Program to illustrate the compareTo() method

import java.util.*;
import java.time.*;
import java.time.chrono.*;

public class GfG {
    public static void main(String[] args)
    {
        // First date
        ChronoLocalDateTime dt
            = LocalDateTime.parse("2018-12-05T19:21:12");
        System.out.println(dt);

        // Second date
        ChronoLocalDateTime dt1
            = LocalDateTime.parse("2018-12-06T19:21:12");
        System.out.println(dt1);

        try {
            // Compare both dates
            System.out.println(dt1.compareTo(dt));
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

2018-12-05T19:21:12
2018-12-06T19:21:12
1

Reference: https://docs.oracle.com/javase/9/docs/api/java/time/chrono/ChronoLocalDateTime.html#compareTo-java.time.chrono.ChronoLocalDateTime-