code: public static void addPrivateDataProvider(String elementName, String namespace,
              PrivateDataProvider provider) {
          String key = XmppStringUtils.generateKey(elementName, namespace);
          privateDataProviders.put(key, provider);
      }
docs: Adds a private data provider with the specified element name and name space. The provider
  will override any providers loaded through the classpath.
  
  @param elementName the XML element name.
  @param namespace the XML namespace.
  @param provider the private data provider.