Esse erro aparece sob o List, mas não consigo resolver. Só oferece como solucão: Remove type arguments.
@Bean
public ViewResolver contentNegotiationViewResolver(ContentNegotiationManager manager){
List<ViewResolver> viewResolvers = new ArrayList<>();
viewResolvers.add(internalResourceViewResolver());
viewResolvers.add(new JsonViewResolver());
ContentNegotiatingViewResolver resolver = new ContentNegotiatingViewResolver();
resolver.setViewResolvers(viewResolvers);
resolver.setContentNegotiationManager(manager);
return resolver;
}