Java Utililty Methods Month Day

Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
return formatDateY_M_D(calendar.getTime());

SimpleDateFormat formatter = new SimpleDateFormat("yyyyMM");
Date mydate = formatter.parse(curmonth);
Calendar cal = Calendar.getInstance();
cal.setTime(mydate);
cal.add(Calendar.MONTH, month);
SimpleDateFormat daytime = new SimpleDateFormat("yyyyMMdd");
cal.set(Calendar.DAY_OF_MONTH, cal.getActualMaximum(Calendar.DAY_OF_MONTH));
return daytime.format(cal.getTime());
...

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

String returndate = "";
Date date = null;
Calendar cl = Calendar.getInstance();
switch (cl.get(2)) {
case 0:
    cl.set(5, 31);
    break;
case 1:
...

SimpleDateFormat sdf_full = new SimpleDateFormat("yyyy-MM-dd");
Calendar cal = Calendar.getInstance();
Date date = null;
try {
    date = sdf_full.parse(sDate + "-01");
} catch (ParseException e) {
    e.printStackTrace();
cal.setTime(date);
int last = cal.getActualMaximum(Calendar.DATE);
return String.valueOf(last);

try {
    java.util.Date date = str2date(curday);
    Calendar rightNow = Calendar.getInstance();
    rightNow.setTime(date);
    return rightNow.get(Calendar.WEEK_OF_MONTH);
} catch (Exception e) {
    e.printStackTrace();
    return 0;
...

try {
    java.util.Date date = str2utilDate(curday);
    Calendar rightNow = Calendar.getInstance();
    rightNow.setTime(date);
    return rightNow.get(Calendar.WEEK_OF_MONTH);
} catch (Exception e) {
    System.out.println("DateUtil.getYearWeek(str) Error:e = " + e);
    return 0;
...

String curYearMonth = getDateTime6String();
String yearMonth = getPreviousYearMonth(curYearMonth);
return yearMonth.substring(0, 4) + "-" + yearMonth.substring(4) + "-01";

Calendar cal = Calendar.getInstance();
Date dt = new Date();
cal.setTime(dt);
cal.set(Calendar.DAY_OF_MONTH, 1);
DateFormat df = getNewDateFormat(shortFormat);
return df.format(cal.getTime());

Date date = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");
String temp = sdf.format(date);
String firstDayInMoth = "";
firstDayInMoth = temp + "-01";
return firstDayInMoth;