In order to do JSON streaming you should on the server side declare a controller method that returns a application/x-json-stream of JSON objects. For example:

Streaming JSON on the Server

Streaming JSON on the Server

import io.micronaut.http.MediaType
import io.micronaut.http.annotation.Controller
import io.micronaut.http.annotation.Get
import io.reactivex.Flowable
import java.time.ZonedDateTime
import java.util.concurrent.TimeUnit
    @Get(value = "/headlines", processes = MediaType.APPLICATION_JSON_STREAM) (1)
    Flowable<Headline> streamHeadlines() {
        Flowable.fromCallable({ (2)
            Headline headline = new Headline()
            headline.setText("Latest Headline at " + ZonedDateTime.now())
            return headline
        }).repeat(100) (3)
          .delay(1, TimeUnit.SECONDS) (4)
    }

Then on the client simply subscribe to the stream using and every time the server emits a JSON object the client will decode and consume it:

Streaming JSON on the Client

        Flowable<Headline> headlineStream = client.jsonStream(GET("/streaming/headlines"), Headline.class); (1)
        CompletableFuture<Headline> future = new CompletableFuture<>(); (2)
            @Override
            public void onSubscribe(Subscription s) {
                s.request(1); (3)
            }
            @Override
            public void onNext(Headline headline) {
                System.out.println("Received Headline = " + headline.getText());
                future.complete(headline); (4)
            }
            @Override
            public void onError(Throwable t) {
                future.completeExceptionally(t); (5)
            }
            @Override
            public void onComplete() {
                // no-op (6)
        });

Streaming JSON on the Client

Streaming JSON on the Client

            val future = CompletableFuture<Headline>() (2)
            headlineStream.subscribe(object : Subscriber<Headline> {
                override fun onSubscribe(s: Subscription) {
                    s.request(1) (3)
                }
                override fun onNext(headline: Headline) {
                    println("Received Headline = " + headline.text!!)
                    future.complete(headline) (4)
                }
                override fun onError(t: Throwable) {
                    future.completeExceptionally(t) (5)
                }
                override fun onComplete() {
                    // no-op (6)
            })