SimpleDateFormat toPattern behaves differently in java 9

Question

DateFormat dateFormat = DateFormat.getDateInstance(DateFormat.SHORT, new Locale("SV", "SE"));
((SimpleDateFormat) dateFormat).toPattern();

In Java 8, this line produces "yyyy-MM-dd", and in Java 9 - "y-MM-dd".

This has some serious issues for our legacy code, is there any way to return the behavior?

Answer 1

    System.setProperty("java.locale.providers", "COMPAT,CLDR");
    DateFormat dateFormat
            = DateFormat.getDateInstance(DateFormat.SHORT, new Locale("sv", "SE"));
    System.out.println(((SimpleDateFormat) dateFormat).toPattern());

Running on my jdk-9.0.4, this prints

yyyy-mm-dd

You might want to set the property using -Dthe command line, it should not have any meaning.

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, :

DateTimeFormatterBuilder.getLocalizedDateTimePattern(
        FormatStyle.SHORT, null, IsoChronology.INSTANCE, new Locale("SV", "SE")));

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