Is there any chance that getDayOfMonth() from org.joda.time.DateTime to return 0 as the first day of the month?

Let's have an example:

We introduce 01.03.2013 in an input field. And then in a method we check for this: 0==dateTime.getDayOfMonth() are there any chances for this to be true? The numbering for the day of the month begins from 0 or 1?

I suspect it's feasible for a custom Chronology to return 0, but none of the "built-in" chronologies will do so, and certainly the common Gregorian/ISO chronologies won't.

In other words, you'd only need to worry about this if you're using deliberately weird chronologies - at which point this is probably the least of your problems.

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