Stack Overflow question http://stackoverflow.com/q/34671186/2587435

ClientProxyTest.java

import java.net.URI;
import java.util.ArrayList;
import java.util.logging.Logger;
import javax.ws.rs.BeanParam;
import javax.ws.rs.Consumes;
import javax.ws.rs.FormParam;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.core.Cookie;
import javax.ws.rs.core.Form;
import javax.ws.rs.core.MultivaluedHashMap;
import javax.ws.rs.core.MultivaluedMap;
import static junit.framework.Assert.assertEquals;
import org.glassfish.jersey.client.proxy.WebResourceFactory;
import org.glassfish.jersey.filter.LoggingFilter;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.test.JerseyTest;
import org.junit.Test;

/**
 * Run it like any other JUnit test. Required dependencies:
 * 
 *  <dependency>
 *      <groupId>org.glassfish.jersey.test-framework.providers</groupId>
 *      <artifactId>jersey-test-framework-provider-grizzly2</artifactId>
 *      <version>2.22.1</version>
 *      <scope>test</scope>
 *  </dependency>
 *  <dependency>
 *      <groupId>org.glassfish.jersey.ext</groupId>
 *      <artifactId>jersey-proxy-client</artifactId>
 *      <version>2.22.1</version>
 *      <scope>test</scope>
 *  </dependency>
 */
public class ClientProxyTest extends JerseyTest {
    
    public static class Bean {
        @HeaderParam("X-Header")
        public String header;
        @FormParam("form-param")
        public String form;
        
    }
    
    public static interface IResource {
        
        @POST
        @Path("{id}")
        @Consumes("application/x-www-form-urlencoded")
        public String post(@BeanParam Bean bean, @PathParam("id") String id);
    }
    
    @Path("resource")
    public static class Resource implements IResource {
        @Override
        public String post(Bean bean, String id) {
            return bean.form + ":" + bean.header + ":" + id;
        }  
    }
    
    @Override
    public ResourceConfig configure() {
        return new ResourceConfig(Resource.class)
                .register(new LoggingFilter(Logger.getAnonymousLogger(), true));
    }
    
    @Override
    public URI getBaseUri() {
        return URI.create(BASE_PATH);
    }
    
    private static final String BASE_PATH = "http://localhost:8080";
    
    @Test
    public void doit() {
        Client client = ClientBuilder.newClient();
        WebTarget target = client.target(BASE_PATH).path("resource");
        MultivaluedMap<String, Object> headers = new MultivaluedHashMap<>();
        headers.putSingle("X-Header", "headerValue");
        Form form = new Form();
        form.param("form-param", "formValue");
        IResource resource = WebResourceFactory.newResource(
                IResource.class, target, true, headers,
                new ArrayList<Cookie>(), form);
        String response = resource.post(null, "idString");
        assertEquals("formValue:headerValue:idString", response);
    }
}