| HttpClient | An HTTP Client. | 
| HttpClient.Builder |  | 
| HttpClient.Redirect | Defines the automatic redirection policy. | 
| HttpClient.Version | The HTTP protocol version. | 
| HttpHeaders | A read-only view of a set of HTTP headers. | 
| HttpRequest | An HTTP request. | 
| HttpRequest.BodyPublisher | A BodyPublisherconverts high-level Java objects into a flow of
 byte buffers suitable for sending as a request body. | 
| HttpRequest.Builder |  | 
| HttpResponse | An HTTP response. | 
| HttpResponse.BodyHandler | A handler for response bodies. | 
| HttpResponse.BodySubscriber | A BodySubscriberconsumes response body bytes and converts them
 into a higher-level Java type. | 
| HttpResponse.PushPromiseHandler | A handler for push promises. | 
| HttpResponse.ResponseInfo | Initial response information supplied to a  BodyHandler
 when a response is initially received and before the body is processed. | 
| HttpTimeoutException | Thrown when a response is not received within a specified time period. | 
| WebSocket | A WebSocket Client. | 
| WebSocket.Builder |  | 
| WebSocket.Listener | The receiving interface of WebSocket. |