import javax.websocket.ClientEndpointConfig;
import javax.websocket.ContainerProvider;
import javax.websocket.DeploymentException;
import javax.websocket.Endpoint;
import javax.websocket.EndpointConfig;
import javax.websocket.HandshakeResponse;
import javax.websocket.Session;
import javax.websocket.WebSocketContainer;
import java.io.IOException;
import java.net.URI;
import java.util.Collections;
import java.util.List;
import java.util.Map;

/**
 * @author erik
 */
public class WebSocketTest {

    private static class Configurator extends ClientEndpointConfig.Configurator {

        Configurator() {
        }

        @Override
        public void beforeRequest(Map<String, List<String>> headers) {
            headers.put("Dummy", Collections.singletonList(String.join("", Collections.nCopies(4000, "A"))));
            super.beforeRequest(headers);
        }

        @Override
        public void afterResponse(HandshakeResponse handshakeResponse) {
            super.afterResponse(handshakeResponse);
        }
    }

    public static void main(String[] args) {

        Endpoint endpoint = new Endpoint() {
            @Override
            public void onOpen(Session session, EndpointConfig endpointConfig) {
            }
        };

        ClientEndpointConfig endpointConfig = ClientEndpointConfig.Builder.create()
                                                      .configurator(new Configurator())
                                                      .build();

        WebSocketContainer container = ContainerProvider.getWebSocketContainer();
        try {
            Session backendSession = container.connectToServer(endpoint, endpointConfig,
                    URI.create("ws://demos.kaazing.com/echo?.kl=Y"));

            backendSession.close();

        } catch (DeploymentException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}