ADDITIONAL SYSTEM INFORMATION :
Windows 10
Linux- Coreos

A DESCRIPTION OF THE PROBLEM :
The swedish wiki does say the their Department of Foreign Affairs have swithced to officially user Belarus from 24. nov 2019, and the their language committee recommends using Belarus as well.
This is just one example with Belarus but there could me more

Test Program-
import java.util.*;

public class testLocale {
           public static void main(String[] args) {

              // create a new locale
              Locale locale = new Locale("ENGLISH", "BY");

              // print locale
              System.out.println("Locale:" + locale);

              // print locale display name - result is based on inLocale
              System.out.println("Display Name:"
                 + locale.getDisplayCountry(new Locale("SV", "SE")));
           }
        }

Sample Output-
Locale:english_BY
Display Name:Vitryssland


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Sample program mentioned
Java version-
openjdk version "16.0.1" 2021-04-20
OpenJDK Runtime Environment AdoptOpenJDK-16.0.1+9 (build 16.0.1+9)
OpenJDK 64-Bit Server VM AdoptOpenJDK-16.0.1+9 (build 16.0.1+9, mixed mode, sharing)

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Belarus
ACTUAL -
Vitryssland

FREQUENCY : always