Hystrix async methods within javanica not running inside spring-boot java application

Question

I am using spring-cloud-starter (ie.. spring boot with all the microservices features). When I create hystrix method in a component annotated using the javanica @HystrixCommand, follow the directions on the javanica github site (https://github.com/Netflix/Hystrix/tree/master/hystrix-contrib/hystrix-javanica) to make that method run async, regardless of whether I use their 'Future<>' or Reactive execution 'Observable<>', nothing runs/executes and I get
java.lang.ClassCastException: springbootdemo.EricComponent$1 cannot be cast to springbootdemo.Eric whenever I attempt to pull the result (in the case of Future<>) or get a callback (in case of Reactive Execution .. and println's dont trigger so it really didnt run).

public class Application { ...
}
@RestController
@RequestMapping(value = "/makebunchofcalls/{num}")
class EricController { ..

    @RequestMapping(method={RequestMethod.POST})
    ArrayList<Eric> doCalls(@PathVariable Integer num) throws IOException {
        ArrayList<Eric> ale = new ArrayList<Eric>(num);
        for (int i =0; i<num; i++) {
            rx.Observable<Eric> oe = this.ericComponent.doRestTemplateCallAsync(i);
            oe.subscribe(new Action1<Eric>() {
                @Override
                public void call(Eric e) {  // AT RUNTIME, ClassCastException
                    ale.add(e);
                }
            });
        }

        return ale;
    }

@Component
class EricComponent { ...

    // async version =========== using reactive execution via rx library from netflix ==============

    @HystrixCommand(fallbackMethod = "defaultRestTemplateCallAsync", commandKey = "dogeAsync")
    public rx.Observable<Eric> doRestTemplateCallAsync(int callNum) {
        return new ObservableResult<Eric>() {
            @Override
            public Eric invoke() {  // NEVER CALLED
                try {
                    ResponseEntity<String> result = restTemplate.getForEntity("http://doges/doges/24232/photos", String.class);  // actually make a call
                    System.out.println("*************** call successfull: " + new Integer(callNum).toString() + " *************");
                } catch (Exception ex) {
                    System.out.println("=============== call " + new Integer(callNum).toString() + " not successfull: " + ex.getMessage() + " =============");
                }
                return new Eric(new Integer(callNum).toString(), "ok");
            }
        };
    }

    public rx.Observable<Eric> defaultRestTemplateCallAsync(int callNum) {
        return new ObservableResult<Eric>() {
            @Override
            public Eric invoke() {
                System.out.println("!!!!!!!!!!!!! call bombed " + new Integer(callNum).toString() + "!!!!!!!!!!!!!");
                return new Eric(new Integer(callNum).toString(), "bomb");
            }
        };
    }
}

Why would I be getting back an EricComponent$1 instead of a Eric? btw, Eric is just a simple class with 2 strings... its ommitted.

I am figuring that I must have to explicitly execute, but that alludes me because: 1) Doing it with Future<> the queue() method is not available as the documentation claims and 2) doing it with Observable<> there really isn't a way to execute it that I get.

Answer 1

Do you have the @EnableHystrix annotation on you application class?

The subscribe method is asynchronous and you are trying to populate a list in a synchronous controller method so there may be a problem there. Can you change the subscribe to toBlockingObservable().forEach() and see if that helps?

Update #1 I was able to duplicate. Your default method should not return an Observable<Eric>, just an Eric.

public Eric defaultRestTemplateCallAsync(final int callNum) {
    System.out.println("!!!!!!!!!!!!! call bombed " + new Integer(callNum) + "!!!!!!!!!!!!!");
    return new Eric(new Integer(callNum).toString(), "bomb");
}

Update #2 See my code here https://github.com/spencergibb/communityanswers/tree/so26372319

Update #3 When I commented out the fallbackMethod attribute, it complained that it couldn't find a public version of EricComponent for AOP. I made EricComponent public static and it worked. A top level class in its own file would work to. My code, linked above, works (assuming the restTemplate call works) and returns n OK.