java - IllegalStateException within method with Response paramether

Question

I wrote a simple class to test response reading entity method (if it works as I expect). But it didn't worked well.

When I launch my class I get following error at response.readEntity():

Exception in thread "main" java.lang.IllegalStateException: Method not supported on an outbound message.  
  at org.glassfish.jersey.message.internal.OutboundJaxrsResponse.readEntity(OutboundJaxrsResponse.java:150)

And here's the code I wrote

public static void main(String[] args) {
        List<Entity> representations = new ArrayList<>();
        representations.add(new Entity("foo", "baz", false));
        representations.add(new Entity("foo1", "baz1", true));
        representations.add(new Entity("foo2", "baz2", false));
        Response build = Response.ok(representations).build();
        printEntitesFromResponse(build);
    }

public static void printEntitesFromResponse(Response response) {
        response
                .readEntity(new GenericType<List<Entity>>() {})
                .stream()
                .forEach(entity -> System.out.println(entity));
    }

What am I doing wrong?

Answer 1

There are two types of Responses, inbound and outbound, though they still use the same interface. Outbound is when you are sending a response from the server-side

Response response = Response.ok(entity).build();

Inbound is when you are receiving the response on the client-side.

Response response = webTarget.request().get();

The readEntity() method is disabled on the server-side outbound response because you don't need it. It's only used when you need to de-serialize the response from the response stream. But there is none when it's outbound.

If you want the entity on the outbound response, just use Response#getEntity()