Calendar cal = Calendar.getInstance(); cal.setFirstDayOfWeek(Calendar.SUNDAY);
Calendar cal = Calendar.getInstance(); cal.setFirstDayOfWeek(Calendar.MONDAY);In this example, we create a new Calendar instance and set its first day of the week as Monday. This is done by passing the constant value `Calendar.MONDAY` to the setFirstDayOfWeek method. The setFirstDayOfWeek method is part of the java.util.Calendar package library.