### Question:
RestAuthLanguageCallbackHandler extends AbstractRestAuthCallbackHandler<LanguageCallback> { public String getCallbackClassName() { return CALLBACK_NAME; }  LanguageCallback handle(HttpServletRequest request, HttpServletResponse response,
            JsonValue postBody, LanguageCallback originalCallback); String getCallbackClassName(); JsonValue convertToJson(LanguageCallback callback, int index); LanguageCallback convertFromJson(LanguageCallback callback, JsonValue jsonCallback);  }### Answer:
@Test public void shouldGetCallbackClassName() { String callbackClassName = restAuthLanguageCallbackHandler.getCallbackClassName(); assertEquals(LanguageCallback.class.getSimpleName(), callbackClassName); }