Java CompletedFuture + Restaasy

Question

Java CompletedFuture + Restaasy

I used Java CompletableFuture, like this one

CompletableFuture.runAsync(() -> {//Some code here });

When I try to use Restaasy Client inside this block of code, I get

javax.ws.rs.ProcessingException: Unable to find a MessageBodyReader of content-type application/json;charset=utf-8 and type class java.lang.String

If I use a client outside of completablefuture, it works. Restaasy code looks something like this:

        ResteasyClient client = new ResteasyClientBuilder().build();
        client.register(new AcceptEncodingFilter("gzip"));
        ResteasyWebTarget target = client.target(exampleURL);

        target = target.queryParam("1", 1)
                .queryParam("2", "1")
                .queryParam("3", 3)
                .queryParam("4", 4)
                .queryParam("5", "5");

        Response response = target.request().get();
        resultString = response.readEntity(String.class);

I ran the resteasy outisde of completablefuture code to “fix” the problem, but would like to understand why this is happening.

The resteasy code inside CompletableFuture is as follows:

CompletableFuture.runAsync(() -> {
            try {
                ResteasyClient client = new ResteasyClientBuilder().build();
                client.register(new AcceptEncodingFilter("gzip"));
                ResteasyWebTarget target = client.target("http://test.com");

                target = target.queryParam("1", "1")
                        .queryParam("2", "2")
                        .queryParam("3", "3")
                        .queryParam("4", "4")
                        .queryParam("5", "5");

                Response response = target.request().get();
                String resultString = response.readEntity(String.class);

                response.close();
                client.close();
            } catch (Exception e){
                e.printStackTrace();
            }
        });