Using JodaTime, in case you don't have Java 8
String timeValue = "2014/11/11";
DateTimeFormatter parseFormat = new DateTimeFormatterBuilder().appendPattern("yyyy/MM/dd").toFormatter();
LocalDate startDate = LocalDate.parse(timeValue, parseFormat);
LocalDate endDate = startDate.plusDays(20);
System.out.println(startDate + "; " + endDate);
Period p = new Period(startDate, endDate);
System.out.println("Days = " + p.getDays());
System.out.println("Weeks = " + p.getWeeks());
System.out.println("Months = " + p.getMonths());
Which outputs...
2014-11-11; 2014-12-01
Days = 6
Weeks = 2
Months = 0
