Java Utililty Methods Day of

Calendar c = Calendar.getInstance();
Date date = null;
date = new SimpleDateFormat("yy-MM-dd").parse(specifiedDay);
c.setTime(date);
int day = c.get(Calendar.DATE);
c.set(Calendar.DATE, day + 1);
String dayAfter = new SimpleDateFormat("yyyy-MM-dd").format(c.getTime());
return dayAfter;
...

Calendar c = Calendar.getInstance();
Date date = null;
try {
    date = new SimpleDateFormat("yyyy-MM-dd").parse(specifiedDay);
} catch (ParseException e) {
    e.printStackTrace();
c.setTime(date);
...

Calendar c = Calendar.getInstance();
c.setTime(date);
int day = c.get(Calendar.DATE);
c.set(Calendar.DATE, day + 1);
c.set(Calendar.HOUR_OF_DAY, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
return c.getTime();
...

return gStandardDayFormat.format(day);

Calendar endCal = Calendar.getInstance();
Date endDate = stringToDate(strEndDate, STRING_DATE_FORMAT);
endCal.setTime(endDate);
endCal.add(Calendar.DATE, -days);
SimpleDateFormat sdf = new SimpleDateFormat(STRING_DATE_FORMAT);
return sdf.format(endCal.getTime());

Calendar calendarEndDate = Calendar.getInstance();
calendarEndDate.setTime(endDate);
calendarEndDate.add(Calendar.DAY_OF_YEAR, 0 - days);
return calendarEndDate.getTime();

Calendar ca = parseStringToCalendar(str);
if (ca == null) {
    return null;
ca.add(Calendar.DATE, n);
String strDate = ca.get(Calendar.YEAR) + "-";
int intMonth = ca.get(Calendar.MONTH) + 1;
if (intMonth < 10) {
...

return new SimpleDateFormat("dd").format(cal.getTime());

SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
Date date = null;
Date targetDate = null;
try {
    date = sdf.parse(day);
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.add(Calendar.DATE, beforeOrAfterDays);
...

return new Date(date.getTime() - (long) 24 * (long) 60 * 60 * 1000);