code: public static IdentifierExtension findFirst(Collection<? extends Extension> extensions)
      {
          for (Extension extension : extensions)
          {
              if (IDENTIFIER_EXTENSION_ID == extension.getId()) return (IdentifierExtension)extension;
          }
          return null;
      }
docs: Returns the first IdentifierExtension found in the given collection of extensions,
  or null if no IdentifierExtensions exist in the given collection.