Java tutorial
//package com.java2s; import java.util.Calendar; import static java.util.Calendar.MONTH; import static java.util.Calendar.YEAR; public class Main { /** * Set the provided calendar to the first day of the month. Also clears all time information. * * @param calendar {@linkplain Calendar} to modify to be at the first fay of the month */ public static void setToFirstDay(Calendar calendar) { int year = getYear(calendar); int month = getMonth(calendar); calendar.clear(); calendar.set(year, month, 1); } public static int getYear(Calendar calendar) { return calendar.get(YEAR); } public static int getMonth(Calendar calendar) { return calendar.get(MONTH); } }