Java.util.ResourceBundle.handleKeySet() Method

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Description

The java.util.ResourceBundle.handleKeySet() method returns a Set of the keys contained only in this ResourceBundle.

Declaration

Following is the declaration for java.util.ResourceBundle.handleKeySet() method

protected Set<String> handleKeySet()

Parameters

NA

Return Value

This method returns a Set of the keys contained only in this ResourceBundle

Exception

NA

Example

The following example shows the usage of java.util.ResourceBundle.handleKeySet() method.

package com.tutorialspoint;

import java.util.*;

public class ResourceBundleDemo extends ResourceBundle {

   @Override
   public Object handleGetObject(String key) {
      if (key.equals("hello")) {
         return "Hello World!";
      } else {
         return null;
      }
   }

   @Override
   public Enumeration getKeys() {
      StringTokenizer key = new StringTokenizer("Hello World!");
      return key;
   }

   protected Set<String> handleKeySet() {
      return new HashSet<String>();
   }

   public static void main(String[] args) {

      // create a new ResourceBundle with specified locale
      ResourceBundle bundle =
      ResourceBundle.getBundle("hello", Locale.US);

      // print the keys
      Enumeration<String> enumeration = bundle.getKeys();
      
      while (enumeration.hasMoreElements()) {
         System.out.println("" + enumeration.nextElement());
      }
   }
}

Assuming we have a resource file hello_en_US.properties available in your CLASSPATH, with the following content. This file will be used as an input for our example program −

hello = Hello World!
bye = Goodbye World!
morning = Good Morning World!

Let us compile and run the above program, this will produce the following result −

hello
bye
morning