Incorrect data returned by Calendar API

Question

In our business requirement we are supposed to find out the first day of the week.

Since the client is European so I used following code to get it.

But, issue is when I run this code I am getting 2 as the answer where as I am expecting 1.

public class Test{
    public static void main(String[] args) {
        TimeZone eu = TimeZone.getTimeZone("Europe/Berlin"); 
        Locale de = Locale.forLanguageTag("de"); 
        int firstDayOfWeek = Calendar.getInstance(eu, de).getFirstDayOfWeek(); 
        System.out.println(firstDayOfWeek);
    }
}

Can some one help me understand this behavior.

Answer 1

Look at the docs:

Gets what the first day of the week is; e.g., SUNDAY in the U.S., MONDAY in France.

and here:

public static final int MONDAY 2

This shows that the return value depends on the locale.

If we print this:

System.out.println(firstDayOfWeek == Calendar.MONDAY);

We'll see true. This means that the first day of week is indeed Monday. It's just that you thought Monday is encoded by 1. In fact, Sunday is encoded as 1.