Date validator with reasons

An exam form asks for the date of birth as dd-mm-yyyy. Write a method checkDate(String text) that throws an IllegalArgumentException with the reason when the date is wrong. Check in this order:

1. use the form dd-mm-yyyy if splitting on - does not give exactly 3 parts,
2. day, month and year must be whole numbers (parseInt throws NumberFormatException),
3. year must be 1 to 9999,
4. month must be 1 to 12,
5. day must be 1 to D, where D is the number of days in that month (29 for February in a leap year).

A leap year is divisible by 4 but not by 100, or divisible by 400. For each line print Valid: <text>, Invalid: <text> (not a number) or Invalid: <text> (<reason>). Finish with Valid dates: V of n.