Few examples show you how to compare two dates in Java. Updated with Java 8 examples.
1. Date.compareTo()
A classic method to compare two java.util.Date in Java.
- Return value is 0 if both dates are equal.
- Return value is greater than 0 , if Date is after the date argument.
- Return value is less than 0, if Date is before the date argument.
TestDate.java
package com.mkyong.date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class TestDate {
    public static void main(String[] args) throws ParseException {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Date date1 = sdf.parse("2009-12-31");
        Date date2 = sdf.parse("2010-01-31");
        System.out.println("date1 : " + sdf.format(date1));
        System.out.println("date2 : " + sdf.format(date2));
        if (date1.compareTo(date2) > 0) {
            System.out.println("Date1 is after Date2");
        } else if (date1.compareTo(date2) < 0) {
            System.out.println("Date1 is before Date2");
        } else if (date1.compareTo(date2) == 0) {
            System.out.println("Date1 is equal to Date2");
        } else {
            System.out.println("How to get here?");
        }
    }
}
Output
date1 : 2009-12-31
date2 : 2010-01-31
Date1 is before Date2
2. Date.before(), Date.after() and Date.equals()
A more user friendly method to compare two java.util.Date
TestDate2.java
package com.mkyong.date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class TestDate2 {
    public static void main(String[] args) throws ParseException {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Date date1 = sdf.parse("2009-12-31");
        Date date2 = sdf.parse("2010-01-31");
        System.out.println("date1 : " + sdf.format(date1));
        System.out.println("date2 : " + sdf.format(date2));
        if (date1.after(date2)) {
            System.out.println("Date1 is after Date2");
        }
        if (date1.before(date2)) {
            System.out.println("Date1 is before Date2");
        }
        if (date1.equals(date2)) {
            System.out.println("Date1 is equal Date2");
        }
    }
}
Output
date1 : 2009-12-31
date2 : 2010-01-31
Date1 is before Date2
3. Calender.before(), Calender.after() and Calender.equals()
Example to compare two java.util.Calendar
TestDate3.java
package com.mkyong.date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class TestDate3 {
    public static void main(String[] args) throws ParseException {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Date date1 = sdf.parse("2009-12-31");
        Date date2 = sdf.parse("2010-01-31");
        System.out.println("date1 : " + sdf.format(date1));
        System.out.println("date2 : " + sdf.format(date2));
        Calendar cal1 = Calendar.getInstance();
        Calendar cal2 = Calendar.getInstance();
        cal1.setTime(date1);
        cal2.setTime(date2);
        if (cal1.after(cal2)) {
            System.out.println("Date1 is after Date2");
        }
        if (cal1.before(cal2)) {
            System.out.println("Date1 is before Date2");
        }
        if (cal1.equals(cal2)) {
            System.out.println("Date1 is equal Date2");
        }
    }
}
Output
date1 : 2009-12-31
date2 : 2010-01-31
Date1 is before Date2
4. Java 8
In Java 8, you can use the new isBefore(), isAfter(), isEqual() and compareTo() to compare LocalDate, LocalTime and LocalDateTime.
Review the following example to compare two java.time.LocalDate
TestDate4.java
package com.mkyong.date;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
public class TestDate4 {
    public static void main(String[] args) {
        DateTimeFormatter sdf = DateTimeFormatter.ofPattern("yyyy-MM-dd");
        LocalDate date1 = LocalDate.of(2009, 12, 31);
        LocalDate date2 = LocalDate.of(2010, 01, 31);
        System.out.println("date1 : " + sdf.format(date1));
        System.out.println("date2 : " + sdf.format(date2));
        System.out.println("Is...");
        if (date1.isAfter(date2)) {
            System.out.println("Date1 is after Date2");
        }
        if (date1.isBefore(date2)) {
            System.out.println("Date1 is before Date2");
        }
        if (date1.isEqual(date2)) {
            System.out.println("Date1 is equal Date2");
        }
        System.out.println("CompareTo...");
        if (date1.compareTo(date2) > 0) {
            System.out.println("Date1 is after Date2");
        } else if (date1.compareTo(date2) < 0) {
            System.out.println("Date1 is before Date2");
        } else if (date1.compareTo(date2) == 0) {
            System.out.println("Date1 is equal to Date2");
        } else {
            System.out.println("How to get here?");
        }
    }
}
Output
date1 : 2009-12-31
date2 : 2010-01-31
Is...
Date1 is before Date2
CompareTo...
Date1 is before Date2
References
- Date CompareTo JavaDoc
- Calendar before after JavaDoc
- LocalDate JavaDoc