REST Service Calls for Java - 1.0

Extension ID

What’s new?

See REST service call for Java - 1.0 - Release Notes  for more information.


This extension provides support for some web services calls from Java.

Supported REST client libraries

  • org.glassfish.jersey.client.JerseyClient
  • org.jboss.resteasy.client.jaxrs.ResteasyClient
  • org.jboss.resteasy.client.jaxrs.ResteasyWebTarget
  • org.jboss.resteasy.client.ClientRequest
  • com.sun.jersey.api.client.Client
  • com.sun.jersey.api.client.WebResource
  • org.springframework.web.client.RestTemplate
  • org.springframework.web.util.UriComponentsBuilder
  • org.springframework.web.util.UriComponents
  • org.springframework.web.util.HtmlUtils
  • org.springframework.web.reactive.function.client.WebClient
  • org.apache.cxf.jaxrs.client.WebClient
  • org.apache.http.client.HttpClient
  • org.apache.http.impl.client.CloseableHttpClient
  • org.apache.http.impl.nio.client.CloseableHttpAsyncClient
  • org.apache.http.client.utils.URIBuilder
  • org.apache.wink.client.Resource

  • org.apache.wink.client.RestClient
  • io.vertx.core.http.HttpClientRequest
  • io.vertx.ext.web.client.HttpRequest
  • io.vertx.ext.web.client.WebClient
  • com.squareup.okhttp.OkHttpClient
  • okhttp3.OkHttpClient
  • org.resthub.web.Client
  • feign.Feign
  • feign.RequestLine
  • retrofit2.http.DELETE

  • retrofit2.http.GET

  • retrofit2.http.PATCH

  • retrofit2.http.POST

  • retrofit2.http.PUT

Function Point, Quality and Sizing support

This extension provides the following support:

  • Function Points (transactions): A green tick indicates that OMG Function Point counting and Transaction Risk Index are supported
  • Quality and Sizing: A green tick indicates that CAST can measure size and that a minimum set of Quality Rules exist
Function Points
Quality and Sizing
(tick) (error)

AIP Core compatibility

This extension is compatible with:

AIP Core release Supported
8.3.x (tick)

Dependencies with other extensions

The REST Service Calls for Java extension requires that ≥ 1.2.8-funcrel of the JEE Analyzer is also installed and used in order to ensure the most complete set of results. This dependency with the JEE Analyzer is not automatically handled when downloading the REST Service Calls for Java extension via CAST Extension Downloader, CAST Server Manager or AIP Console, therefore you must MANUALLY download and install the JEE Analyzer  before starting an analysis.

What results can you expect?


This extension analyzes web service calls made from Java code through classic fluent APIs. For example with com.sun.jersey:

import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;

class Main
    public static void main(String[] args) {
        Client client = Client.create();

        WebResource webResource = client

        ClientResponse response = webResource.accept("application/json")



Client side load balancing

Usage of allows to choose a service to call so impacts the URL called:

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.client.RestTemplate;

class Main
    private LoadBalancerClient loadBalancerClient;

    void f()
        RestTemplate client ;
        ServiceInstance serviceInstance = loadBalancerClient.choose("user-auth");
        String path = serviceInstance.getUri().toString() + "/oauth/token";
        client.put(path, client);


Feign is a declarative web service client which makes writing web service clients easier. Native sample: “RequestLine” annotation indicates the presence of feign web service:

interface GitHub {
  @RequestLine("GET /repos/{owner}/{repo}/contributors")
  List<Contributor> contributors(@Param("owner") String owner, @Param("repo") String repo);
public static class Contributor {
  String login;
  int contributions;
public class MyApp {
  public static void main(String... args) {
    GitHub github = Feign.builder()
                         .decoder(new GsonDecoder())
                         .target(GitHub.class, "");
    // Fetch and print a list of the contributors to this library.
    List<Contributor> contributors = github.contributors("OpenFeign", "feign");
    for (Contributor contributor : contributors) {
      System.out.println(contributor.login + " (" + contributor.contributions + ")");

“FeignClient” annotation associated with “RequestMapping” and “GetMapping” annotations indicates the presence of feign web service:

import java.util.List;
        name = "${}",
        path= "${client.path}",
        configuration = FeignConfiguration.class
public interface ClientConfiguration {
    @RequestMapping(method = RequestMethod.POST, value = "/services/clients")
    List<SupplierTransitionDTO> getData(@RequestBody List<String> codes) throws FeignException;

@FeignClient(name = "Client", url = "${build.api.url}", path = "/api/v1")
public interface ClientConfiguration {

    ConsentResponse getConfiguration(
            @PathVariable("site-id") String siteId,
            @RequestParam("types") List<ConfigType> types);


With Retrofit 2, endpoints are defined inside an interface using special retrofit annotations to encode details about the parameters and request method. Annotations like “GET”, “POST”, “PUT”, “DELETE” and “PATCH”, for example:

import retrofit2.http.GET;

public interface ExampleGetService {
    Single<ExampleApi> getMode();


The following objects are displayed in CAST Enlighten:

Icon Description

Delete Resource Service

Get Resource Service

Post Resource Service

Put Resource Service
Patch Resource Service




  • When the code uses a custom URL builder, we cannot evaluate the URL.
  • When the standard java API is encapsulated in a custom method where the “http method” (put, get, post, delete) is passed as a parameter, the dynamic evaluation will generally fail.
class MyHttpCall
   void execute(String url, String method)
      Client client = ClientBuilder.newClient();
      WebTarget myResource =;

      if (method == "GET")
          String response = myResource.request(MediaType.TEXT_PLAIN).get(String.class);
      else if (method == "PUT")

  • Manual creation of feign clients is not supported