Java tutorial
import java.time.DayOfWeek; import java.time.LocalDate; import java.time.Month; import java.time.temporal.TemporalAdjusters; public class Main { public static void main(String[] args) { LocalDate date = LocalDate.of(2014, Month.JULY, 16); System.out.println(date); LocalDate firstDayOfJuly = date.with(TemporalAdjusters.firstDayOfMonth()); // 2014-07-01 System.out.println(firstDayOfJuly); LocalDate dateOfFirstMonday = date.with(TemporalAdjusters.firstInMonth(DayOfWeek.MONDAY)); // 2014-07-07 System.out.println(dateOfFirstMonday); } }