Fixing HttpClient warning "Invalid expires attribute" using fluent API

For the developers don't want to think on the object model, wrapping the HttpClient for a RestTemplate might be used as below ( as @comiventor mentioned above especially for Spring Boot Developers).

a Customizer for RestTemplate,

public class RestTemplateStandardCookieCustomizer 
                         implements RestTemplateCustomizer {

    @Override
    public void customize(final RestTemplate restTemplate) {

        final HttpClient httpClient = HttpClients.custom()
            .setDefaultRequestConfig(RequestConfig.custom()
                .setCookieSpec(CookieSpecs.STANDARD).build())
            .build();

        restTemplate.setRequestFactory(
          new HttpComponentsClientHttpRequestFactory(httpClient)
        );
    }
}

and using it with the RestTemplate Builder

var restTemplate = restTemplateBuilder.additionalCustomizers(
            new RestTemplateStandardCookieCustomizer()
        ).build();

The default HttpClient has difficulty understanding the latest RFC-compliant headers.

Instead of hiding the warning, just switch to a standard cookie spec like this (HttpClient 4.4+):

HttpClient httpClient = HttpClients.custom()
        .setDefaultRequestConfig(RequestConfig.custom()
                .setCookieSpec(CookieSpecs.STANDARD).build())
        .build();

If you want to use HttpClientBuilder you can use the following sytax:

        HttpClient httpClient = HttpClientBuilder.create()
            .setDefaultRequestConfig(RequestConfig.custom()
                    .setCookieSpec(CookieSpecs.STANDARD).build()).build();