@Test
  void defaultCallingProxiedMethod() throws Exception {
    server.enqueue(new MockResponse().setBody("response data"));

    String url = "http://localhost:" + server.getPort();
    TestInterface api = Feign.builder().target(TestInterface.class, url);

    Response response = api.defaultMethodPassthrough();
    assertThat(Util.toString(response.body().asReader(Util.UTF_8))).isEqualTo("response data");
    assertThat(server.takeRequest()).hasPath("/");
  }
Shows exception handling isn't required to coerce 204 to null or empty
core/src/test/java/feign/FeignBuilderTest.java