Java.util.ResourceBundle.containsKey() Method

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Description

The java.util.ResourceBundle.containsKey(String key) method determines whether the given key is contained in this ResourceBundle or its parent bundles.

Declaration

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

public boolean containsKey(String key)

Parameters

key − the resource key

Return Value

This method returns true if the given key is contained in this ResourceBundle or its parent bundles; false otherwise.

Exception

NullPointerException − if key is null

Example

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

package com.tutorialspoint;

import java.util.Locale;
import java.util.ResourceBundle;

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

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

      // print the text assigned to key "hello"
      System.out.println("" + bundle.getString("hello"));

      // check if the bundle contains "bye" key
      System.out.println("" + bundle.containsKey("bye"));

      // check if the bundle contains "hello" key
      System.out.println("" + bundle.containsKey("hello"));
   }
}

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!

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

Hello World!
false
true