Java DateFormat issue on Mac vs Windows

Question

I am using the code below on Mac OSX 10.10.2 and it's behaving strangely.

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

public class StringToDate {

    public static void main(String[] args) throws Exception {
        String dateInString = "23/Oct/2015";
        DateFormat formatter = new SimpleDateFormat("dd/MMM/YYYY");
        Date date = formatter.parse(dateInString);
        System.out.println(date);
    }
}

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Output on Mac:         Sun Dec 28 00:00:00 CST 2014

Output on Windows: Fri Oct 23 00:00:00 CDT 2015

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Why is the Mac output wrong?

Answer 1

Y is for the week year. Use y for the year.

DateFormat formatter = new SimpleDateFormat("dd/MMM/yyyy");

Also, make sure the DateFormat's locale is the right one.

EDIT:

A Date has millisecond precision, so if you want nanosecond precision, you shouldn't use Date and SimpleDateFormat.

S is for milliseconds. Since you tell SimpleDateFormat that the last part of the string is milliseconds, it parses it as that: 545000000 milliseconds (i.e. a bit more than 6 days, which explains the difference between the input and the output).

To get an accurate result, to the millisecond, remove the last 6 characters of the string, and use the pattern "dd-MMM-yyyy-HH.mm.ss.SSS".