ADDITIONAL SYSTEM INFORMATION :
Oracle OpenJDKReference Java 17, OpenJDK Java 21, Amazon Corretto Java 11 and Java 17 and Eclipse Adoptium Java 11

A DESCRIPTION OF THE PROBLEM :
The displayed country names for the ISO 3166 alpha-2 codes CD and CG do not give the current country but the one in the past.

ISO.org registration
https://www.iso.org/obp/ui/#iso:code:3166:CD the Democratic Republic of the Congo has alpha-2 code CD and alpha-3 code COD
https://www.iso.org/obp/ui/#iso:code:3166:CG the Republic of the Congo has alpha-2 code CG and alpha-3 code COG

The Dutch list of official countries from the Rijksdienst voor Identiteitsgegevens is published in the pdf "Tabel 34 Landen (gesorteerd op omschrijving)" on the page:
https://publicaties.rvig.nl/Landelijke_tabellen/Landelijke_tabellen_32_t_m_61_excl_tabel_35/Landelijke_Tabellen_32_t_m_61_in_pdf_formaat
Democratische Republiek Congo is listed on page 6 and Congo, Congo-Kinshasa and Congo-Brazzaville on page 10 and Zaïre on page 2

Congo-Brazzaville ended on 15-08-1960 and became Congo on 15-08-1960
Congo-Kinshasa ended on 27-10-1971 became Zaïre on 27-10-1971 till 17-05-1997 and then the Democratische Republiek Congo on 17-05-1997


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
System.out.println(new Locale("", "CD").getDisplayCountry(new Locale("nl", "NL")));
System.out.println(new Locale("", "CG").getDisplayCountry(new Locale("nl", "NL")));


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Democratische Republiek Congo
Congo
ACTUAL -
Congo-Kinshasa
Congo-Brazzaville

---------- BEGIN SOURCE ----------
import java.util.Locale;

public class LocaleTest {
    public static void main(String[] args) {
        System.out.println(new Locale("", "CD").getDisplayCountry(new Locale("nl", "NL")));
        System.out.println(new Locale("", "CG").getDisplayCountry(new Locale("nl", "NL")));
    }
}

---------- END SOURCE ----------

FREQUENCY : always