Parsing Ambiguous Dates in Java

Question

Is there any way in Java to guess the date format when it is not explicitly defined?

For example a user types in 11Mar09 or 11-09-2009 or 11/09/2009 or 11-09 what is

Answer 1

As the domain of possible date-strings are infinite, I don't see how it could be possible to recognize them all. You can however pick a subset for pattern-matching.

You give no clues about your user-interface, but the best approach here would be to help the user input the date. For example with a pop-up calendar or just forcing a predefined format.