Why I obtain a wrong result when I create a new Date starting from the year, the month and the day in this Java application?

Question

I have some problem trying to create a Date in Java, starting from the year, the month and the day.

So, I have created this simple utility method that creates my date:

private Date creaDataNascita(int birthYear, int birthMonth, int birthDay) {

    Date dataNascita = new Date(birthYear, birthMonth, birthDay);

    return dataNascita;

}

I have the following values for the input parameters (I checked it with the debugger.):

birthYear = 1984
birthMonth = 4
birthDay = 12

The problem is that this line:

Date dataNascita = new Date(birthYear, birthMonth, birthDay);

creates me a strange date, its value in fact is: 12-mag-3884.

Why? What is wrong? What am I missing? How can I fix this issue?

don't use the `Date` constructor - its deprecated and its evil — Reimeus, Apr 11 '16 at 13:48
http://stackoverflow.com/questions/5677470/java-why-is-the-date-constructor-deprecated-and-what-do-i-use-instead — assylias, Apr 11 '16 at 13:48
Please search Stack Overflow before posting. Your question has been handled many times already. — Basil Bourque, Apr 11 '16 at 15:54

score 3 · Accepted Answer · answered Apr 11 '16 at 13:52

The Date Javadoc notes

A year y is represented by the integer y - 1900.

A month is represented by an integer from 0 to 11; 0 is January, 1 is February, and so forth; thus 11 is December.

To get the correct Date with the deprecated Date constructor, it would need to be something like new Date(birthYear - 1900, birthMonth - 1, birthDay); but I would prefer LocalDate like

int birthYear = 1984;
int birthMonth = 4;
int birthDay = 12;
LocalDate ld = LocalDate.of(birthYear, birthMonth, birthDay);
System.out.println(ld);

Output is

1984-04-12

score -1 · Answer 2 · answered Apr 11 '16 at 13:50

-1

As said in the javadoc :

Date(int year, int month, int day) Deprecated. instead use the constructor Date(long date)
Date(long date) Constructs a Date object using the given milliseconds time value.

answered Apr 11 '16 at 13:50

Aeldred

314
2
15

score -1 · Answer 3 · answered Apr 11 '16 at 13:51

-1

As referenced in https://docs.oracle.com/javase/8/docs/api/java/util/Date.html,

The Date class is deprecated, Use Calendar.set instead.

answered Apr 11 '16 at 13:51

Peixiang Zhong

419
4
8

What does it being deprecated have to do with the value it produces? Is the value random? – Savior Apr 11 '16 at 13:51
1

The `java.util.Date` class is *not* deprecated. Many of its methods and constructors are, but the class itself is not. – Ian McLaird Apr 11 '16 at 14:01

Why I obtain a wrong result when I create a new Date starting from the year, the month and the day in this Java application?

3 Answers3