Java Utililty Methods Day Add

try {
 SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd");
 Calendar cd = Calendar.getInstance();
 cd.setTime(format.parse(String.valueOf(date)));
 cd.add(Calendar.DAY_OF_YEAR, days);
 return format.format(cd.getTime());
} catch (ParseException e) {
 throw new RuntimeException(e);
...

SimpleDateFormat df = new SimpleDateFormat("dd/MM/yyyy");
long d = df.parse(date).getTime();
long millis = d + ((long) day) * 24 * 3600 * 1000;
return df.format(new Date(millis));

long time = d.getTime();
day = day * 24 * 60 * 60 * 1000;
time += day;
return new Date(time);

Calendar calendar = Calendar.getInstance();
long millis = getMillis(date) + day * 24L * 3600L * 1000L;
calendar.setTimeInMillis(millis);
return calendar.getTime();

java.util.Calendar c = java.util.Calendar.getInstance();
c.setTimeInMillis(getMillis(date) + ((long) day) * 24 * 3600 * 1000);
return c.getTime();

Date oldDate = new Date();
long curTimeStamp = 0;
try {
 oldDate = format.parse(date);
} catch (ParseException e) {
 return date;
curTimeStamp = oldDate.getTime();
...

Date date = null;
SimpleDateFormat sdate = new SimpleDateFormat("yyyy-MM-dd");
GregorianCalendar gc = new GregorianCalendar();
try {
 date = (Date) sdate.parse(str);
 gc.setTime(date);
 gc.add(field, dayNum);
} catch (ParseException e) {
...

return add(d, Calendar.DATE, amount);

Calendar c = Calendar.getInstance();
c.setTime(date);
c.add(Calendar.DAY_OF_MONTH, day);
return c.getTime();

Calendar cal = Calendar.getInstance();
cal.setTime(date);
cal.add(Calendar.DATE, day);
return cal.getTime();