Locale getExtensionKeys() Method in Java with Examples

Last Updated : 01 May, 2019

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()); 
    } 
} 