title: Is ResourceBundleControlProvider virtually deprecated in Java?
body: <p>The official <a href="http://docs.oracle.com/javase/8/docs/api/java/util/spi/ResourceBundleControlProvider.html" rel="nofollow noreferrer">Oracle documentation</a> for <code>ResourceBundleControlProvider</code> says:</p>
  
  <blockquote>
    <p>Provider implementations must be packaged using the <a href="http://docs.oracle.com/javase/8/docs/technotes/guides/extensions/index.html" rel="nofollow noreferrer">Java Extension Mechanism</a> as installed extensions. ...</p>
    
    <p><strong>Since: 1.8</strong></p>
  </blockquote>
  
  <p>However, when you click on the mentioned <a href="http://docs.oracle.com/javase/8/docs/technotes/guides/extensions/index.html" rel="nofollow noreferrer">Java Extension Mechanism</a> link, it says:</p>
  
  <blockquote>
    <p>This feature <strong>has been deprecated</strong> and will be removed in a future release.</p>
  </blockquote>
  
  <p>Does this mean that the <code>ResourceBundleControlProvider</code> interface was introduced to Java 1.8 as already deprecated? Shall we start using it at all? Why is it there?</p>
  
  <p>It looks like it has been introduced to Java 8 by mistake, as <a href="https://bugs.openjdk.java.net/browse/JDK-8171189" rel="nofollow noreferrer">Deprecate ResourceBundleControlProvider for removal</a> Open JDK bug suggests:</p>
  
  <blockquote>
    <p>This interface was introduced in JDK 8 (JDK-6380549) for a convenient way to replace the default Control with the provided one, using the Java Extension Mechanism, which is now obsolete in JDK 9. The original requestor of this feature confirms that they haven't used this API. It turned out that to our knowledge, there seem to be no users of this interface. Adding <code>@Deprecated</code> tag with <code>forRemoval=true</code> in JDK 9, and removing the interface in JDK 10 may be appropriate. </p>
  </blockquote>
  
  <p>The interface looks like a stillborn feature, it's way of usage is so weird and impractical.</p>