Instant isAfter() method in Java with Examples

isAfter() method of an Instant class is used to check if this instant is after the instant passed as parameter or not. This method returns a boolean value showing the same.

Syntax:

public boolean isAfter(Instant otherInstant)

Parameter: This method takes a parameter otherInstant which is the other instant to compare to this instant. It should not be null.

Returns: This method returns true if this instant is after the specified instant. Else it returns false.

Exception: This method throws NullPointerException if otherInstant passed as the parameter is null.

Below programs illustrate the isAfter() method:

Program 1:

// Java program to demonstrate
// Instant.isAfter() method

import java.time.*;

public class GFG {
    public static void main(String[] args)
    {

        // create a Instant object
        Instant instant1
            = Instant.parse("2018-12-30T19:34:50.63Z");

        // create other Instant
        Instant instant2
            = Instant.parse("2018-12-29T09:24:00.63Z");

        // print instances
        System.out.println("Instance 1: " + instant1);
        System.out.println("Instance 2: " + instant2);

        // check if instant1 is after instant2
        // using isAfter()
        boolean value = instant1.isAfter(instant2);

        // print result
        System.out.println("Is Instant1 after Instant2: "
                           + value);
    }
}

Output:

Instance 1: 2018-12-30T19:34:50.630Z
Instance 2: 2018-12-29T09:24:00.630Z
Is Instant1 after Instant2: true

Program 2:

// Java program to demonstrate
// Instant.isAfter() method

import java.time.*;

public class GFG {
    public static void main(String[] args)
    {

        // create a Instant object
        Instant instant1
            = Instant.parse("2018-10-30T19:34:50.63Z");

        // create other Instant
        Instant instant2 = Instant.now();

        // print instances
        System.out.println("Instance 1: " + instant1);
        System.out.println("Instance 2: " + instant2);

        // check if instant1 is after instant2
        // using isAfter()
        boolean value = instant1.isAfter(instant2);

        // print result
        System.out.println("Is Instant1 after Instant2: "
                           + value);
    }
}

Output:

Instance 1: 2018-10-30T19:34:50.630Z
Instance 2: 2018-11-27T04:52:08.970Z
Is Instant1 after Instant2: false

Program 3: To show Exception thrown by isAfter()

// Java program to demonstrate
// Instant.isAfter() method

import java.time.*;

public class GFG {
    public static void main(String[] args)
    {

        // create a Instant object
        Instant instant1
            = Instant.parse("2018-10-30T19:34:50.63Z");

        // create other Instant
        Instant instant2 = null;

        try {

            // print instances
            System.out.println("Instance 1: " + instant1);
            System.out.println("Instance 2: " + instant2);

            // check if instant1 is after instant2
            // using isAfter()
            boolean value = instant1.isAfter(instant2);
        }
        catch (Exception e) {
            // print result
            System.out.println("Exception: " + e);
        }
    }
}

Output:

Instance 1: 2018-10-30T19:34:50.630Z
Instance 2: null
Exception: java.lang.NullPointerException

References: https://docs.oracle.com/javase/10/docs/api/java/time/Instant.html#isAfter(java.time.Instant)