ChronoZonedDateTime isBefore() method in Java with Examples

The isBefore() method of ChronoZonedDateTime interface in Java is used to check if the date, passed as the parameter, is before this ChronoZonedDateTime instance or not. It returns a boolean value showing the same.

Syntax:

public boolean isBefore(ChronoZonedDateTime otherDate)

Parameter: This method accepts a parameter otherDate which specifies the other date-time to be compared to this ChronoZonedDateTime. It should not be null.

Returns: The function returns boolean value showing if this date-time is before the specified date-time.

Below programs illustrate the ChronoZonedDateTime.isBefore() method:

Program 1:

// Program to illustrate the isBefore() method

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

public class GfG {
    public static void main(String[] args)
    {
        // Parses the date
        ChronoZonedDateTime dt1
            = ZonedDateTime.parse(
                "2018-12-06T19:21:12.123+05:30[Asia/Calcutta]");

        // Prints the date
        System.out.println(dt1);

        // Parses the date
        ChronoZonedDateTime dt2
            = ZonedDateTime.parse(
                "2018-10-06T19:21:12.123+05:30[Asia/Calcutta]");

        // Prints the date
        System.out.println(dt2);

        // Compares both dates
        System.out.println(dt1.isBefore(dt2));
    }
}

Output:

2018-12-06T19:21:12.123+05:30[Asia/Calcutta]
2018-10-06T19:21:12.123+05:30[Asia/Calcutta]
false

Program 2:

// Program to illustrate the isBefore() method

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

public class GfG {
    public static void main(String[] args)
    {
        // Parses the date
        ChronoZonedDateTime dt1
            = ZonedDateTime.parse(
                "2018-10-06T19:21:12.123+05:30[Asia/Calcutta]");

        // Prints the date
        System.out.println(dt1);

        // Parses the date
        ChronoZonedDateTime dt2
            = ZonedDateTime.parse(
                "2018-12-06T19:21:12.123+05:30[Asia/Calcutta]");

        // Prints the date
        System.out.println(dt2);

        // Compares both dates
        System.out.println(dt1.isBefore(dt2));
    }
}

Output:

2018-10-06T19:21:12.123+05:30[Asia/Calcutta]
2018-12-06T19:21:12.123+05:30[Asia/Calcutta]
true

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