Java Utililty Methods Week Day

Calendar cal = Calendar.getInstance();
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
cal.setTime(df.parse(date));
cal.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);
return df.format(cal.getTime());

String weekday;
Date date = new Date();
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
int week_index = calendar.get(Calendar.DAY_OF_WEEK) - 1;
switch (week_index) {
case 0: {
    weekday = "sunday";
...

Calendar c = Calendar.getInstance();
int dayOfWeek = c.get(Calendar.DAY_OF_WEEK);
switch (dayOfWeek) {
case 2:
    return "monday";
case 3:
    return "tuesday";
case 4:
...

int weekDay = Calendar.getInstance().get(Calendar.DAY_OF_WEEK);
System.out.println(weekDay);
String weekDay1 = String.valueOf(weekDay);
return weekDay1;

Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
return calendar.get(Calendar.DAY_OF_WEEK);

return getFormat(week).format(date);

Calendar cal = new GregorianCalendar();
cal.setTime(dt);
if (weekDay == 7) {
    weekDay = 1;
} else {
    weekDay++;
cal.set(GregorianCalendar.DAY_OF_WEEK, weekDay);
...

if (weekday == 1) {
    return Calendar.MONDAY;
} else if (weekday == 2) {
    return Calendar.TUESDAY;
} else if (weekday == 3) {
    return Calendar.WEDNESDAY;
} else if (weekday == 4) {
    return Calendar.THURSDAY;
...

return formatDateTime(parse(date), "EE");

SimpleDateFormat sd = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat sdw = new SimpleDateFormat("E");
Date d = null;
try {
    d = sd.parse(date);
} catch (ParseException e) {
    e.printStackTrace();
    d = new Date();
...