Calendar calendar = Calendar.getInstance();

    calendar.set(Calendar.YEAR, 2016);

    calendar.set(Calendar.MONTH, 02);

    int  day = calendar.getActualMaximum(Calendar.DATE);

    calendar.set(Calendar.DAY_OF_MONTH, day);

    String lastDayOfMonth = (new SimpleDateFormat("yyyy-MM-dd")).format(calendar.getTime());

    System.out.println(lastDayOfMonth);