Unable to transfer list of dates to client side widget

Hi,

I have a custom widget with a shared state as follows:

public Date month;
    public List<Date> monthDays

I am setting the state for "monthDays" in the setValue method of my server side component (AbstractField):

@Override
    public void setValue(List<Date> monthDays) throws ReadOnlyException, ConversionException {
        super.setValue(monthDays);
        getState().monthDays = monthDays;
    }

Here, the list of dates is still correct as logging output confirms.

However, in the connector class, I get a list with 2 dates, but both dates are 0 (respectively some day in 1970):

@OnStateChange("monthDays")
    void updateMonthDays() {
        getWidget().setMonthDays(getState().monthDays);
    }

The single month field (called "month") is transferred correctly. Only the values in the list are changed.
Only other difference I can see between the two fields is that I set the shared state for the month in the constructor of the server-side component (AbstractField), while I set the list of dates in the overridden setValue() method.

I am using Vaadin 7.7.0.

Any ideas?
Thanks,
Dominic

OKay I debugged into this and this seems to be a bug in Vaadin. This is part of the JSON received on client side:

"48": {
            "month": 1.4726808E12,
            "monthDays": [{
                "date": 23,
                "hours": 15,
                "minutes": 2,
                "month": 8,
                "seconds": 57,
                "time": 1.474635777926E12,
                "year": 116
            },
            {
                "date": 18,
                "hours": 0,
                "minutes": 0,
                "month": 8,
                "seconds": 0,
                "time": 1.4741496E12,
                "year": 116
            }]
        },

Now the JSONDezerializer find an entry for "month" of type java.util.Date. The Date_Serializer is able to dezerialize the time correctly:

new Date((long) jsonValue.asNumber());

For the monthDays, the Deserializer finds a list of java.util.Date objects. It will loop through the list and try to dezerialize the entries with the Date_Serializer. However, this time it is not a number, but a JSONObject. jsonValue.asNumber() will return NaN, casting this to long will return 0. Which explains why my date is 1970.

I guess I should open a ticket at the bug tracker.

EDIT: For reference, here is the ticket: https://dev.vaadin.com/ticket/20329