Java Utililty Methods Month Day

String ntime = "";
try {
    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
    Date startDate = df.parse(time);
    int nowMonth = startDate.getMonth() + 1;
    int nextMonth = nowMonth + 1;
    int nowYear = startDate.getYear() + 1900;
    String nextTime = nowYear + "-" + nextMonth + "-1";
...

if (yyyy == null || yyyy.trim().equals("")) {
    yyyy = getYear();
if (mm == null || mm.trim().equals("")) {
    mm = getMonth();
int year = Integer.parseInt(yyyy);
int month = Integer.parseInt(mm);
...

int mondayPlus;
Calendar cal = Calendar.getInstance();
cal.setTime(new Date());
cal.set(Calendar.DAY_OF_MONTH, 1);
return getDate(cal.getTime());

Date date = new Date();
int nowMonth = date.getMonth() + 1;
int nowYear = date.getYear() + 1900;
String startTime = nowYear + "-" + nowMonth + "-1";
return startTime;

Calendar c = Calendar.getInstance();
c.setTime(date);
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH);
c.clear();
c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, month);
c.set(Calendar.DAY_OF_MONTH, 1);
...

SimpleDateFormat format = new SimpleDateFormat("yyyy-MM");
Date d = null;
try {
    d = format.parse(date);
} catch (Exception e) {
    e.printStackTrace();
Calendar cal = Calendar.getInstance();
...

if (date == null)
    return null;
String dateStr = format(date, "yyyy-MM") + "-01";
Long mill = parseDate(dateStr).getTime();
T another = (T) date.clone();
another.setTime(mill);
return another;

Calendar c = Calendar.getInstance();
c.setTime(parse(month, "yyyy-MM"));
c.set(Calendar.DATE, 1);
int dayNum = c.get(Calendar.DAY_OF_WEEK);
c.add(Calendar.DATE, 1 - dayNum);
return c.getTime();

Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
return convertDate(calendar.getTimeInMillis());

SimpleDateFormat sdf = new SimpleDateFormat("dd");
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
return sdf.format(calendar.getTime());