private Integer integerHeader(Response response, String header) {
    final MultivaluedMap<String, String> headers = response.getStringHeaders();
    if (!headers.containsKey(header)) {
      return null;
    }

    try {
      return Integer.valueOf(headers.getFirst(header));
    } catch (final NumberFormatException e) {
      // not a number or too big to fit Integer
      return null;
    }
  }
This module directs Feign's http requests to javax.ws.rs.client.Client . Ex:

<pre>
GitHub github =
    Feign.builder().client(new JaxRSClient()).target(GitHub.class, "https://api.github.com");
</pre>
jaxrs2/src/main/java/feign/jaxrs2/JAXRSClient.java