Here you can find the source of isoDayOfWeek(int javaDayOfWeek)
private static int isoDayOfWeek(int javaDayOfWeek)
//package com.java2s; //License from project: Open Source License import java.util.Calendar; public class Main { private static int isoDayOfWeek(int javaDayOfWeek) { switch (javaDayOfWeek) { case Calendar.MONDAY: return 1; case Calendar.TUESDAY: return 2; case Calendar.WEDNESDAY: return 3; case Calendar.THURSDAY: return 4; case Calendar.FRIDAY: return 5; case Calendar.SATURDAY: return 6; case Calendar.SUNDAY: return 7; default:/*from w w w . j a v a2 s . co m*/ throw new IllegalArgumentException("Invalid day of week " + javaDayOfWeek); } } }