code: public final void initializeParsers(final Extension extension, final String moduleName, final XMLMapper xmlMapper) {
          ExtensionParsingContextImpl parsingContext = new ExtensionParsingContextImpl(moduleName, xmlMapper);
          extension.initializeParsers(parsingContext);
          parsingContext.attemptCurrentParserInitialization();
      }
docs: Ask the given {@code extension} to
  {@link Extension#initializeParsers(ExtensionParsingContext) initialize its parsers}. Should be used in
  preference to calling {@link #getExtensionParsingContext(String, XMLMapper)} and passing the returned
  value to {@code Extension#initializeParsers(context)} as this method allows the registry to take
  additional action when the extension is done.
  
  @param extension  the extension. Cannot be {@code null}
  @param moduleName the name of the extension's module. Cannot be {@code null}
  @param xmlMapper  the {@link XMLMapper} handling the extension parsing. Can be {@code null} if there won't
  be any actual parsing (e.g. in a slave Host Controller or in a server in a managed domain)