Locale getExtensionKeys() Method in Java with Examples

The getExtensionKeys() method of Locale class in Java is used to return a set of extension keys associated with this locale which cannot be modified and the keys remains in lower-case. If there is no extension then the method returns an empty set.
Syntax:
public Set <Character> getExtensionKeys()
Parameters: This method does not take any parameters.
Return Value: This method either returns a set of extension keys associated with this locale or an empty set if it has no extensions.
Below programs illustrate the working of getExtensionKeys() method:
Program 1:
// Java code to illustrate// getExtensionKeys() method  import java.util.*;  public class Locale_Demo {    public static void main(String[] args)    {          // Creating a new locale        Locale first_locale            = new Locale("th", "TH", "TH");          // Displaying first locale        System.out.println("Locale: "                           + first_locale);          // Displaying the set        System.out.println("The KeySet: "                           + first_locale.getExtensionKeys());    }} |
Output:
Locale: th_TH_TH_#u-nu-thai The KeySet: [u]
Program 2:
// Java code to illustrate// getExtensionKeys() method  import java.util.*;  public class Locale_Demo {    public static void main(String[] args)    {          // Creating a new locale        Locale first_locale            = new Locale("en", "US");          // Displaying first locale        System.out.println("Locale: "                           + first_locale);          // Displaying the set        System.out.println("The KeySet: "                           + first_locale.getExtensionKeys());    }} |
Output:
Locale: en_US The KeySet: []
Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Locale.html#getExtensionKeys()



