<dependency> <groupId>joda-time</groupId> <artifactId>joda-time</artifactId> <version>2.10.7</version> </dependency> import org.joda.time.DateTime; import org.joda.time.Days; public class DateCalculator { public static void main(String[] args) { DateTime startDate = new DateTime(2021, 1, 1, 0, 0); DateTime endDate = new DateTime(2021, 1, 31, 0, 0); int daysDifference = Days.daysBetween(startDate, endDate).getDays(); } }