Date compareTo(Date) in Java

compareTo(Date): This method is available in java.util.Date class of Java.

Syntax:

int java.util.Date.compareTo(Date anotherDate)

This method takes one argument of type Date as its parameter. This method compares two Dates for ordering.

Parameters: One parameter is required for this method.

anotherDate: the Date to be compared.

Returns:

1. The value 0 if the argument Date is equal to this Date.

2. A value less than 0 if this Date is before the Date argument.

3. A value greater than 0 if this Date is after the Date argument.

Throws:

NullPointerException - if anotherDate is null.

Approach 1: When no exception

Java

import java.util.Date;

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

        Date date = new Date();

        Date anotherDate = new Date();
        System.out.println(date.compareTo(anotherDate));

    }
}

Output:

0

Approach 2: NullPointerException

Java

import java.util.Date;

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

        Date date = new Date();

        Date anotherDate = null;
        System.out.println(date.compareTo(anotherDate));

    }
}

Output:

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "date" is null
	at java.base/java.util.Date.getMillisOf(Date.java:957)
	at java.base/java.util.Date.compareTo(Date.java:980)