You must use at least one, but no more than one http method annotation on for reaseasy proxy client

Question

I am trying to implement a simple client in rest easy, but I am getting an error saying "You must use at least one, but no more than one http method annotation". In my server implementation, I have added a http annotation on my method.

    @Path("/")
public class TestResource
{
    @GET
    @Path("/domain/{value}")
    public String get(@PathParam("value") final String value) {
        return "Hello" + value;
    }
}

I debugged it through, the first time it is not hitting the runtime exception, However, it is making a second call to it and failing, not sure why and how.

My client as junit test:

@Test
public void testPerformRestEasy() {

    ResteasyClient client = new ResteasyClientBuilder().build();
    ResteasyWebTarget target = client.target("http://localhost:8080/");
    TestResource proxy = target.proxy(TestResource.class);
    String response = proxy.get("user");
    Assert.assertEquals("Hellouser", response);
}

The code where it is failing

    private static <T> ClientInvoker createClientInvoker(Class<T> clazz, Method method, ResteasyWebTarget base, ProxyConfig config)
   {
      Set<String> httpMethods = IsHttpMethod.getHttpMethods(method);
      if (httpMethods == null || httpMethods.size() != 1)
      {
         throw new RuntimeException("You must use at least one, but no more than one http method annotation on: " + method.toString());
      }
      ClientInvoker invoker = new ClientInvoker(base, clazz, method, config);
      invoker.setHttpMethod(httpMethods.iterator().next());
      return invoker;
   }

Error:

java.lang.RuntimeException: You must use at least one, but no more than one http method annotation on: public final void java.lang.Object.wait(long,int) throws java.lang.InterruptedException
    at org.jboss.resteasy.client.jaxrs.ProxyBuilder.createClientInvoker(ProxyBuilder.java:76)
    at org.jboss.resteasy.client.jaxrs.ProxyBuilder.proxy(ProxyBuilder.java:52)
    at org.jboss.resteasy.client.jaxrs.ProxyBuilder.build(ProxyBuilder.java:120)
    at org.jboss.resteasy.client.jaxrs.internal.ClientWebTarget.proxy(ClientWebTarget.java:72)

Does anyone know what the issue is here?

Answer 1

The Resteasy JAXRS 2 client does not seem to accept implementation classes directly. To make it work, you have to create a properly annotated interface. It is used by Resteasy to generate a client proxy and your server must implement exactly the same interface.

So in your case, you have to split your code into an interface and a separate implementation class:

@Path("/")
public interface TestResource {
    @GET
    @Path("/domain/{value}")
    String get(@PathParam("value") final String value);
}

public class TestResourceImpl implements TestResource {
    @Override String get(final String value) {
        return "Hello" + value;
    }
}

I'm not sure if this is Resteasy-specific or required by the specification, but solved the same issue for me. You can find the section that gave me the hint here in the documentation.

Answer 2

You have to define the MIME media type resource representation of resource(@Produces/@Consumes) from client. Like -

@Path("/")
public class TestResource
{
    @GET
    @Produces("text/plain")
    @Path("/domain/{value}")
    public String get(@PathParam("value") final String value) {
        return "Hello" + value;
    }
} 

The Jboss Client framework Doc will help you more.