The compareTo() method of Java Date class compares two dates and sort them for order.
Syntax:
public int compareTo(Date anotherDate)
Parameters: The function accepts a single parameter anotherDate which specifies the date to be compared .
Return Value: The function gives three return values specified below:
- It returns the value 0 if the argument Date is equal to this Date.
- It returns a value less than 0 if this Date is before the Date argument.
- It returns a value greater than 0 if this Date is after the Date argument.
Exception: The function throws a single exception that is NullPointerException if anotherDate is null.
Program below demonstrates the above mentioned function:
// Java code to demonstrate// compareTo() function of Date class  import java.util.Date;import java.util.Calendar;public class GfG {    // main method    public static void main(String[] args)    {          // creating a Calendar object        Calendar c = Calendar.getInstance();          // set Month        // MONTH starts with 0 i.e. ( 0 - Jan)        c.set(Calendar.MONTH, 11);          // set Date        c.set(Calendar.DATE, 05);          // set Year        c.set(Calendar.YEAR, 1996);          // creating a date object with specified time.        Date dateOne = c.getTime();          System.out.println("Date 1: "                           + dateOne);          // creating a date of object        // storing the current date        Date currentDate = new Date();          System.out.println("Date 2: "                           + currentDate);          // compares        System.out.println("On Comparison: "                           + currentDate                                 .compareTo(dateOne));    }} |
Output:
Date 1: Thu Dec 05 08:17:55 UTC 1996 Date 2: Wed Jan 02 08:17:55 UTC 2019 On Comparison: 1
// Java code to demonstrate// compareTo() function of Date class  import java.util.Date;  public class GfG {    // main method    public static void main(String[] args)    {          // creating a date of object        // stospecified datent date        Date currentDate = new Date();          System.out.println("Date 1: " + currentDate);          // specifiedDate is assigned to null.        Date specifiedDate = null;          System.out.println("Date 2: " + specifiedDate);          System.out.println("Passing null as parameter: ");        try {            // throws NullPointerException            System.out.println(currentDate                                   .compareTo(specifiedDate));        }        catch (Exception e) {            System.out.println("Exception: " + e);        }    }} |
Output:
Date 1: Wed Jan 02 08:18:02 UTC 2019 Date 2: null Passing null as parameter: Exception: java.lang.NullPointerException
