what does this error mean?
Exception in thread "AWT-EventQueue-0" java.time.DateTimeException: Invalid value for MonthOfYear (valid values 1 - 12): 0 It only happens for the month of January
this is my line of code
public int computeAge(Date birthDay) throws ParseException { LocalDate birthdate = LocalDate.of(birthDay.getYear(), birthDay.getMonth(), birthDay.getDay()); LocalDate curDate = LocalDate.now(); Period p = Period.between(birthdate, curDate); return p.getYears(); } This happens because Date uses month numbers from 0 to 11, but LocalDate uses month numbers from 1 to 12. So even if your program doesn't throw the DateTimeException, it won't give you the correct result.
Please stop using the Date class, and just use classes from the java.time package instead. Those particular methods - getDay(), getMonth() and getYear() were deprecated last century, if I recall correctly.
In this case, you should use LocalDate instead of Date, because it expresses a combination of year, month and day, with no time component.
Date. As a secondary piece we can well add in case you cannot do that, convert (which, as you said, was exactly what OP was trying). And yes, unfortunately there are still very many situations where we interact with legacy code and cannot readily avoid Date.