[EXTERNAL] Re: 4-letter patterns in Date Format Style no longer give full text style

[Naoto Sato]

On 7/10/23 12:49 PM, Bruno Borges wrote:
> Given that "en_US" is well known and commonly a user input data, what is 
> then the ideal way to create a Locale object for such string input?

Then use Locale.forLanguageTag(). It will accept BCP 47 Langauge tag. 
You will need to replace `_` with `-`.

> 
> And isn't this the case of a breaking change more than just updating the 
> time database used by default in JDK?

You could specify the system property `java.locale.providers` to COMPAT 
to use the JDK8 locales (although this has been deprecated in JDK21). 
However, expecting US resources with Locale("en_US") is incorrect in the 
first place.

> 
> Perhaps in other words, shouldn't Locale(String) constructor attempt to 
> parse the input for the Locale(String, String) constructor so the 
> behavior would have been maintained in accordance to Java 8?

Don't think so. The spec of Locale(String) is clear that it won't do any 
syntactic checks on the input. Otherwise if someone had been creating 
"xxx_yyy" as a language, it will break.

Naoto

> 
> Sent from mobile device.
> ------------------------------------------------------------------------
> *From:* Naoto Sato <naoto.sato at oracle.com>
> *Sent:* Monday, July 10, 2023 12:36:10 PM
> *To:* Bruno Borges <Bruno.Borges at microsoft.com>; 
> core-libs-dev at openjdk.org <core-libs-dev at openjdk.org>
> *Subject:* [EXTERNAL] Re: 4-letter patterns in Date Format Style no 
> longer give full text style
> Hi,
> 
> In your test case,
> 
> ```
> new Locale("en_US");
> ```
> 
> This will fall back to ROOT locale texts with CLDR (default since JDK9)
> where it differs from US English. Probably you may want to `new
> Locale("en", "US)` or preferably use `Locale.US` constant.
> 
> Naoto
> 
> On 7/10/23 12:08 PM, Bruno Borges wrote:
>> Hi all,
>> 
>> Was there any change to Date Time Formatter API that made the "EEEE" and 
>> the "MMMM" (and other 4-letter patterns) change from Java 8 to 11+ ?
>> 
>> In Java 8, "EEEE" with locale en_US correctly gives the FULL day of 
>> week, e.g., "Monday".
>> 
>> In Java 11 and 17 (two I've tested), the same input will give "Mon".
>> 
>> I've also tested for "MMMM" expecting "July" (as in 8), but in 11/17 I 
>> get only "Jul".
>> 
>> Here's a test case:
>> 
>> brunoborges/date-formatting-bug at f8f84a1 (github.com) 
>> <https://github.com/brunoborges/date-formatting-bug/actions/runs/5511890139/jobs/10048031299 <https://urldefense.com/v3/__https://github.com/brunoborges/date-formatting-bug/actions/runs/5511890139/jobs/10048031299__;!!ACWV5N9M2RV99hQ!JFb8UvDcd0yJhPFTBgCl61gnX6IBN2X7VtRBoKwvcLBkHwCJxL6QM52A6g7Lq960cGc9hgiqdusTFB7YMNgvlIdG$>>
>> 
>> 
>> Thanks,
>> Bruno