Jersey 2.11 and ResourceMethodInvocationHandlerProvider : MessageBodyWriter not found

Question

I saw a lot of people had struggled with "MessageBodyWriter not found" using Jersey (2.11 for me) for a REST server, but none of their problems seem to be related to my case.

I had a simple REST method, everything was working fine. Then I moved to a custom ResourceMethodInvocationHandlerProvider.

I implement ResourceMethodInvocationHandlerProvider:

public class MyResourceHandlerProvider implements ResourceMethodInvocationHandlerProvider{

    public void someMethodInvokedEarly() {

        Set<Class<?>> res = new HashSet<Class<?>>();
        res.add(some.package.MyInteface.class);
        res.add(some.package.MyException.class);

        ResourceConfig packagesResourceConfig = new ResourceConfig(res);
        packagesResourceConfig.register(JacksonFeature.class);
        packagesResourceConfig.registerInstances(new org.glassfish.hk2.utilities.binding.AbstractBinder() {
            @Override
            protected void configure() {
                bind(MyResourceHandlerProvider.class).to(ResourceMethodInvocationHandlerProvider.class);
            }
        });
    }

    @Override
    public InvocationHandler create(Invocable arg0) {
        return new MyInvocationHandler();
    }
}

As you see I give him MyInvocationHandler that is like this:

public class MyInvocationHandler implements InvocationHandler {

    final MyIntefaceImplemented target = GlobalItems.myIntefaceImplementedInstance;
    public MyInvocationHandler() {

        Class<?>[] clazz = new Class<?>[1];
        clazz[0] = some.package.MyInterface.class;

    }

    @Override
    public Object invoke(Object obj, Method method, Object[] args)
            throws Throwable {

        GenericEntity entity = null;
        Object ret = method.invoke(target , args);

        if(ret instanceof List<?>) {
            entity = new GenericEntity<List>((List)p) {};

        }
        return Response.status(Status.OK).entity(entity).type(MediaType.APPLICATION_JSON).build();
    }
}

If I don't go through this, I get a response 200, with a well formated body.

But when I go through this, I get a

GRAVE: MessageBodyWriter not found for media type=text/xml, type=class org.glassfish.jersey.message.internal.OutboundJaxrsResponse, genericType=java.util.List<java.lang.String>.

I believe dependencies / registration is not the problem because I got a 200 response before.

Do you have any idea of what could be the cause? Thank you.

Regards, Yutanpo/湯たんぽ

Edit :

More precision. The invocated method

Object ret = method.invoke(target , args);

Does not return a Response. It seems that this is where the problem lies.

The thing is that I want to make "MyInterfaceImplemented" fully available through web services without having to modify its methods return types. This is why I had the idea of implementing the InvocationHandler, to act as a Java Proxy.

Answer 1

Solved.

I thought that

packagesResourceConfig.register(JacksonFeature.class);

and

res.add(JacksonJaxbJsonProvider.class);
ResourceConfig packagesResourceConfig = new ResourceConfig(res);

would be somehow equivalent, but they are not. The second fixed the problem (also in the invocation handler I have to return the entity, not the response)