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

    String url = "http://localhost:" + server.getPort();
    Encoder encoder = (object, bodyType, template) -> template.body(object.toString());

    TestInterface api = Feign.builder().encoder(encoder).target(TestInterface.class, url);
    api.encodedPost(Arrays.asList("This", "is", "my", "request"));

    assertThat(server.takeRequest()).hasBody("[This, is, my, request]");
  }
Shows exception handling isn't required to coerce 204 to null or empty
core/src/test/java/feign/FeignBuilderTest.java