Obtenha dia a partir da data do mês de Java
Calendar cal = Calendar.getInstance();
cal.set(year,month-1,day);
int nd = cal.get(Calendar.DAY_OF_WEEK);
Noobie Nareshhhh
Calendar cal = Calendar.getInstance();
cal.set(year,month-1,day);
int nd = cal.get(Calendar.DAY_OF_WEEK);Calendar cal = Calendar.getInstance();
cal.set(Calendar.DATE, cal.getActualMaximum(Calendar.DATE));
Date lastDayOfMonth = cal.getTime();