Feign Client Get Request HttpStatus 200 but body is null when json is very long

Question

I have an issue with my Feign client, I get the response as well when the json not containing lot of data. But when a json is very long I get 200 status inside Response Object but body is null:

@FeignClient(name = "processSvc", url = "${xxx}")
public interface ProcessClient {

  
    @GetMapping(value = "/v1/process/{uid}", produces = "application/json")
    Response readProcess(@PathVariable("uid") String uid);
}

Any proposition for resolve this issue?

Answer 1

The issue was reading a response that is larger than the entire memory allocated to the current process. So, streaming the response fixed the issue by getting the body as InputStream, then convert it to String via IOUtils.toString():

Response response = null;
        String json;
        try {
             response = processClient.readProcess(uid);
             json = IOUtils.toString(response.body().asInputStream(), Charsets.UTF_8.name());
        } catch (IOException e) {
                throw new RuntimeException(e);
        }