JDK-8190918 : Retrieve the region specific data regardless of language in locale
  • Type: Bug
  • Component: core-libs
  • Sub-Component: java.util:i18n
  • Affected Version: 8,9,10
  • Priority: P3
  • Status: Closed
  • Resolution: Fixed
  • Submitted: 2017-11-08
  • Updated: 2021-08-07
  • Resolved: 2017-12-12
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JDK 10
10 b36Fixed
Related Reports
Relates :  
JDK-8177568 - JEP 314: Additional Unicode Language-Tag Extensions
Relates :  
JDK-8272117 - weekOfYear off by one week for Locale.GERMAN
Description
For the region specific data, we would get the data from CLDR only regards to the region settings in locale. In current implementation, if we use an "invalid" locale, e.g. "zh-ES", as this locale hasn't been handled correctly when need to search the region specific information, so we would get the data from root resource bundle. 

===== Code 
    public static void main(String[] args) {
        Locale normLocale = Locale.forLanguageTag("es-ES");
        Locale oddLocale = Locale.forLanguageTag("zh-ES");
        print(normLocale);
        print(oddLocale);
    }

    private static void print(Locale loc) {
        Calendar ca = Calendar.getInstance(loc);
        int minDayInFirstWeek = ca.getMinimalDaysInFirstWeek();
        int firstDayOfWeek = ca.getFirstDayOfWeek();
        System.out.println("minDay: "+minDayInFirstWeek +" firstDay: "+firstDayOfWeek);
    }
===== Output
minDay: 4 firstDay: 2
minDay: 1 firstDay: 1

===== Expected:
minDay: 4 firstDay: 2
minDay: 4 firstDay: 2