Asynchronous RESTful web service client

This section describes the usage of the asynchronous JAX-RS API on the client for calling the RESTful web APIs.

To invoke a REST API asynchronously on the client, you use javax.ws.rs.client.AsyncInvoker. The AsyncInvoker instance is obtained from the call of the Invocation.Builder.async() method, as shown in the following code:

//Other imports are omitted for brevity 
import javax.ws.rs.client.AsyncInvoker; 
import javax.ws.rs.client.Client; 
import javax.ws.rs.client.WebTarget; 
import javax.ws.rs.core.GenericType; 
import javax.ws.rs.core.Response; 
 
String BASE_URI =  
    "http://localhost:8080/hr-services/webresources";  
Client client = ClientBuilder.newClient(); 
WebTarget webTarget = 
     client.target(BASE_URI).path("hr").path("departments"); 
AsyncInvoker asyncInvoker =  
    webTarget.request(APPLICATION_JSON...