This example show us how to use Joda-Time’s DateTime class to get the last day of the month. To get the last day of the month we first need to find out the last date of the month. To do this, create a new instance of a DateTime. From the DateTime object get the day-of-the-month property by calling the dayOfMonth() method. Then call the withMaximumValue() method which will give us the last date of a month.

To get the day name, we call the DateTime‘s dayOfWeek() method followed by a call to the getAsText() method to get the name of the day. Let’s see the code snippet below:

package org.kodejava.joda;

import org.joda.time.DateTime;
import org.joda.time.LocalDate;

public class LastDayOfTheMonth {
    public static void main(String[] args) {
        // Creates an instance of DateTime.
        DateTime dateTime = DateTime.now();

        // Get the last date of the month using the dayOfMonth property
        // and get the maximum value from it.
        DateTime lastDate = dateTime.dayOfMonth().withMaximumValue();

        // Print the date and day name.
        System.out.println("Last date of the month = " + lastDate);
        System.out.println("Last day of the month  = " +
                lastDate.dayOfWeek().getAsText());

        // If you know the last date of the month you can simply parse the
        // date string and get the name of the last day of the month.
        String day = LocalDate.parse("2021-10-31").dayOfWeek().getAsText();
        System.out.println("Day  = " + day);
    }
}

If you know the last date of the month you can simply parse the date string to create a DateTime object or a LocalDate object and call the dayOfWeek() method and get the name of the day using getAsText() method.

The example output is:

Last date of the month = 2021-10-31T06:37:18.069+08:00
Last day of the month  = Sunday
Day  = Sunday

Maven Dependencies

<dependency>
    <groupId>joda-time</groupId>
    <artifactId>joda-time</artifactId>
    <version>2.12.5</version>
</dependency>

This code snippet show you how to convert Joda-Time’s DateTime object into JDK’s java.util.Calendar or java.util.Date object. To convert DateTime to java.util.Date we use the toDate() method and to convert to java.util.Calendar we use the toCalendar() method.

package org.kodejava.joda;

import org.joda.time.DateTime;

import java.util.Calendar;
import java.util.Date;
import java.util.Locale;

public class DateTimeToDateCalendarDemo {
    public static void main(String[] args) {
        // Converting DateTime object into JDK's Date.
        DateTime dateTime = DateTime.now();
        Date date = dateTime.toDate();
        System.out.println("org.joda.time.DateTime = " + dateTime);
        System.out.println("java.util.Date         = " + date);

        // Converting DateTime object into JDK's Calendar.
        Calendar calendar = dateTime.toCalendar(Locale.getDefault());
        System.out.println("java.util.Calendar     = " + calendar);
    }
}

The result of our code snippet:

org.joda.time.DateTime = 2021-10-29T06:54:29.003+08:00
java.util.Date         = Fri Oct 29 06:54:29 CST 2021
java.util.Calendar     = java.util.GregorianCalendar[time=1635461669003,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="Asia/Shanghai",offset=28800000,dstSavings=0,useDaylight=false,transitions=31,lastRule=null],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2021,MONTH=9,WEEK_OF_YEAR=44,WEEK_OF_MONTH=5,DAY_OF_MONTH=29,DAY_OF_YEAR=302,DAY_OF_WEEK=6,DAY_OF_WEEK_IN_MONTH=5,AM_PM=0,HOUR=6,HOUR_OF_DAY=6,MINUTE=54,SECOND=29,MILLISECOND=3,ZONE_OFFSET=28800000,DST_OFFSET=0]

Maven Dependencies

<dependency>
    <groupId>joda-time</groupId>
    <artifactId>joda-time</artifactId>
    <version>2.12.5</version>
</dependency>

The following example show you a various way to create an instance of Joda-Time’s DateTime class. By using the default constructor we will create an object with the current system date time. We can also create the object by passing the information like year, month, day, hour, minutes and second.

Joda can also use an instance from JDK’s java.util.Date and java.util.Calendar to create the DateTime. This means that the date object of JDK and Joda can be used to work together in our application.

package org.kodejava.joda;

import org.joda.time.DateTime;
import org.joda.time.format.DateTimeFormat;

import java.util.Calendar;
import java.util.Date;

public class DateTimeDemo {

    public static void main(String[] args) {
        // Creates DateTime object using the default constructor will
        // give you the current system date.
        DateTime date = new DateTime();
        System.out.println("date = " + date);

        // Or simply calling the now() method.
        date = DateTime.now();
        System.out.println("date = " + date);

        // Creates DateTime object with information like year, month,
        // day, hour, minute, second and milliseconds
        date = new DateTime(2021, 10, 29, 0, 0, 0, 0);
        System.out.println("date = " + date);

        // Create DateTime object from milliseconds.
        date = new DateTime(System.currentTimeMillis());
        System.out.println("date = " + date);

        // Create DateTime object from Date object.
        date = new DateTime(new Date());
        System.out.println("date = " + date);

        // Create DateTime object from Calendar object.
        Calendar calendar = Calendar.getInstance();
        date = new DateTime(calendar);
        System.out.println("date = " + date);

        // Create DateTime object from string. The format of the
        // string  should be precise.
        date = new DateTime("2021-10-29T06:30:00.000+08:00");
        System.out.println("date = " + date);
        date = DateTime.parse("2021-10-29");
        System.out.println("date = " + date);
        date = DateTime.parse("29/10/2021",
                DateTimeFormat.forPattern("dd/MM/yyyy"));
        System.out.println("date = " + date);
    }
}

The result of our code snippet:

date = 2021-10-29T06:30:01.068+08:00
date = 2021-10-29T06:30:01.147+08:00
date = 2021-10-29T00:00:00.000+08:00
date = 2021-10-29T06:30:01.148+08:00
date = 2021-10-29T06:30:01.148+08:00
date = 2021-10-29T06:30:01.166+08:00
date = 2021-10-29T06:30:00.000+08:00
date = 2021-10-29T00:00:00.000+08:00
date = 2021-10-29T00:00:00.000+08:00

Maven Dependencies

<dependency>
    <groupId>joda-time</groupId>
    <artifactId>joda-time</artifactId>
    <version>2.12.5</version>
</dependency>

The org.joda.time.DateMidnight class represent a date time information with the time value set to midnight. The following snippet show you how to instantiate this class.

package org.kodejava.joda;

import org.joda.time.DateMidnight;
import org.joda.time.format.DateTimeFormat;

public class DateMidnightDemo {
    public static void main(String[] args) {
        // Create DateMidnight object of the current system date.
        DateMidnight date = new DateMidnight();
        System.out.println("date = " + date);

        // Or using the now().
        date = DateMidnight.now();
        System.out.println("date = " + date);

        // Create DateMidnight object by year, month and day.
        date = new DateMidnight(2021, 10, 29);
        System.out.println("date = " + date);

        // Create DateMidnight object from milliseconds.
        date = new DateMidnight(System.currentTimeMillis());
        System.out.println("date = " + date);

        // Parse a date from string.
        date = DateMidnight.parse("2021-10-29");
        System.out.println("date = " + date);

        // Parse a date from string of specified patter.
        date = DateMidnight.parse("29/10/2021", 
                DateTimeFormat.forPattern("dd/MM/yyyy"));
        System.out.println("date = " + date);
    }
}

The result of our code snippet:

date = 2021-10-29T00:00:00.000+08:00
date = 2021-10-29T00:00:00.000+08:00
date = 2021-10-29T00:00:00.000+08:00
date = 2021-10-29T00:00:00.000+08:00
date = 2021-10-29T00:00:00.000+08:00
date = 2021-10-29T00:00:00.000+08:00

Maven Dependencies

<dependency>
    <groupId>joda-time</groupId>
    <artifactId>joda-time</artifactId>
    <version>2.12.5</version>
</dependency>