Hi, I want to parse a simple date, and I don't kno...

# getting-started

[Ayfri]

Hi, I want to parse a simple date, and I don't know why this doesn't work

val versionDate =  "May 5, 2009"
	val formattedDate = SimpleDateFormat("MMM d, yyyy").parse(versionDate)
	println(formattedDate)

What am I doing wrong ?

[Kirill Grouchnikov]

image.png

[Kirill Grouchnikov]

You need to be more specific about the "doesn't work" part

[Ayfri]

I'm using Kotlin 1.6.0 & JDK 17

[Rob Elliot]

Might be locale related?

Different issue, but if possible use `DateTimeFormatter`:

import java.time.LocalDate
import java.time.format.DateTimeFormatter
import java.util.Locale.ENGLISH

val versionDate =  "May 5, 2009"
val formatter: DateTimeFormatter = DateTimeFormatter.ofPattern("MMM d, yyyy", ENGLISH)
LocalDate.parse(versionDate, formatter)

[Rob Elliot]

SimpleDateFormat is not threadsafe, which has bitten thousands of people who thought they could use it safely across threads. And Date (which is what it returns) & its companion Calendar are considered some of the worst designed classes of all time.

[ribesg]

My guess also, maybe your default locale doesn’t know May

[Ayfri]

Ah yes maybe, I'm french so I sure have to modify the locale

[Ayfri]

yes it works thanks !

[ribesg]

Yup https://pl.kotl.in/JZmqkFxOG

[ribesg]

(But yeah use java.time, SimpleDateFormat is like 25 years old or something)

[Ayfri]

Ah, what I have to use in java.time

[Rob Elliot]

Posted above

[Ayfri]

Ah nice thanks !

[Ayfri]

Also, my date can have 5 or 15 for the day, do I have to really handle both cases depending on the date length or is there a pattern or something for this ?

[Rob Elliot]

Just tested it - your pattern works fine with May 15, 2009

[ribesg]

The doc clearly states it

Number: […] For parsing, the number of pattern letters is ignored unless it’s needed to separate two adjacent fields.

[ribesg]

You would use dd if you wanted to format 5 to 05, but for parsing there is no reason to use more than d

[Colton Idle]

im learning about dates more now and this was helpful. definitely need a rule that disallows using java.util date and calendar and any other "old" classes like formatters.