Strange behavior with february when calculate period and espessially the month calculation

[aky0]

about the february month there is a strange behavior that you can see in the incorect results with jodatime, you can look down here :

        DateTime date4 = new DateTime(2013, 5, 29, 0, 0, 0, 0);
        DateTime date4PlusNineMonths = new DateTime(2014, 2, 28, 0, 0, 0, 0);
        Period period4 = new Period(date4, date4PlusNineMonths);
        //Incorrect result
        System.out.print(date4.toString("dd/MM/YYYY")+".plusMonths(9) = "+ date4.plusMonths(9).toString("dd/MM/YYYY"));
        System.out.print(period4.getYears() +"Years/"+ period4.getMonths() +"Months/"+ period4.getWeeks() +"Weeks/"+ period4.getDays() +"Days");

Output :
29/05/2013.plusMonths(9) = 28/02/2014 //incorrect result should be 01/03/2014
0Years/9Months/0Weeks/0Days

This is an incorrect calculation It should be 0Years/8Months/4Weeks/2Days Isn't it...?

If it is correct so why when I increase two days more (30 and 31) it always give me the same calculation (0Years/9Months/0Weeks/0Days) we all agree that days are really decreasing or am I dreaming...?

Now maybe I wrong in my use of the joda framework because in the app I develop I do a check everyday on a period to have the precise month separation between two date (toDay and the next date) and if I have 9months and 1day it's too late I need to have 9months and 0days as required in my app =/

If I wrong how can I achieve this please...?

[jodastephen]

This is the correct result, I've updated the Javadoc. It may not be the obvious result, but it does work in that startDate.plus(calculatedPeriod)=endDate.

There is no functionality to match what you want. However the Period.fieldDifference() method may help you.