By returning the private String[] object through the public method you are also giving the outside world read/write access to the contents of the object.
To satisfy the concept you would need to do it this way:
public class MyCalendar
{
private String[] weekdays =
{ "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun" };
public const String[] getWeekdays()
{
return weekdays;
}
}
Now you are allowing the outside world to read the Days of the Week, but now the outside world cannot change the contents of the object.