Jersey does not see my MessageBodyReader

Question

I'm trying to use jersey with my own json MessageBodyReader/MessageBodyWriter (as I am not use @XmlRootElement... annotations on my domain classes).

@Provider
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public final class MyGsonMessageBodyHandler implements MessageBodyWriter<Object>, MessageBodyReader<Object> {
...
}

Jersey uses this class as messagebodywriter (as it stops at breakpoint in the implemented method writeTo). Hovewer it does not see this class as messagebodyreader (and even when I break up this class to the separate implementations of the messagebodyreader/messagebodywriter it still refuses to use my messagebodyreader).

The testing code looks as follows (jersey-grizzly):

final Greeting greeting = resource.path("/greeting")
            .queryParam("name", name)
            .accept(MediaType.APPLICATION_JSON)
            .type(MediaType.APPLICATION_JSON)
            .get(Greeting.class);

The error I got looks as follows:

A message body reader for Java class test.Greeting, and Java type class test.Greeting, and MIME media type application/json was not found

I'm wondering what kind of magic is required for writing own MessageBodyReader?

Answer 1

After a while I found a root cause of the issue. My implementation of MessageBodyReader/Writer is OK (and I it works fine with RESTlet), but IF YOU USE JerseyTest, DO NOT FORGET TO ADD YOUR MessageBodyReader/Writer to it's ClientConfig:

/**
 * Creates custom REST client config which is mandatory since we don't use any JSON providers.
 * @return Jersey Client Config with the required classes to read/write in(out)coming data.
 */
private static ClientConfig createClientConfig() {
    final ClientConfig config = new DefaultClientConfig();
    config.getClasses().add(GsonMessageBodyHandler.class);
    config.getClasses().add(GsonAwareContextResolver.class);
    return config;
}

/**
 * Public ctor
 * @throws com.sun.jersey.test.framework.spi.container.TestContainerException On error
 */
public MyRestExposureTest() throws TestContainerException {
    super(new WebAppDescriptor.Builder("my.rest.package")
            .clientConfig(createClientConfig())
            .contextPath("/")
            .build());
}

Otherwise your client code would be unable to read/write your POJOs.