This is how to use the Response type correctly:
private void getRequest() {
Client client = ClientBuilder.newClient();
String url = "http://localhost:8080/api/masterdataattributes";
WebTarget target = client.target(url);
Response res = target
.request(MediaType.APPLICATION_JSON)
.get();
int status = res.getStatus();
String json = res.readEntity(String.class);
System.out.println(String.format("Status: %d, JSON Payload: %s", status, json));
}
If you're just interested in the payload, you could also just issue a get(String.class). But usually you will also want to check the response status, so working with the Response is usually the way to go.
If you want a typed (generic) JSON response, you could also have readEntity return a Map, or a list of Map if the response is an array of objects as in this example:
List<Map<String, Object>> json = res.readEntity(new GenericType<List<Map<String, Object>>>() {});
String id = (String) json.get(0).get("id");
System.out.println(id);