Java tutorial
//package com.java2s; import java.util.ArrayList; import java.util.Calendar; import java.util.List; public class Main { public static List<Integer> getAllDayInMonth(int month, int year) { List<Integer> listDate = new ArrayList<Integer>(); Calendar calendar = Calendar.getInstance(); calendar.set(year, month, 1); calendar.clear(Calendar.HOUR); calendar.clear(Calendar.MINUTE); calendar.clear(Calendar.SECOND); int totalDays = calendar.getActualMaximum(Calendar.DAY_OF_MONTH); for (int i = 1; i <= totalDays; i++) { listDate.add(i); } return listDate; } }