I am using the org.jboss.resteasy.client.jaxrs.ResteasyClientBuilder to build a REST client in the following way:
ResteasyClient client = (new ResteasyClientBuilder())
.maxPooledPerRoute(5)
.connectionPoolSize(10)
.socketTimeout(10L, TimeUnit.SECONDS)
.register(jacksonProvider)
.register(new RestClientLogger())
.register(new RestClientMDCFilter())
.build();
The jacksonProvider that is registered there is a ResteasyJackson2Provider jacksonProvider = new ResteasyJackson2Provider(); which comes with a custom ObjectMapper that is important for deserialization. So far so good, the problem is, that I get the following warning in JBoss:
10:31:38,414 WARN [org.jboss.resteasy.resteasy_jaxrs.i18n] (default-threads - 1) RESTEASY002155: Provider class org.jboss.resteasy.plugins.providers.jackson.ResteasyJackson2Provider is already registered. 2nd registration is being ignored.
This makes sense if I check the documentation when there already has been an instance of the same class that has been registered before. I used a decompiler to check what ResteasyClientBuilder is doing and was able to see, that it scans the classpath for jars that contain a resource that describes what "built in" providers should be registered.
One of the jboss provided implementations is now apparently already defining a ResteasyJackson2Provider that is registered there making it impossible for me to later register my own instance of it.
What are my options here? I need to get my version of the ResteasyJackson2Provider - or at least the ObjectMapperinto the client. Can I somehow replace the existing one?
I had the same issue, but I did not want to remove the resteasy-jackson2-provider dependencies because we added that dependency explicitly for other parts of the system (using undertow, not full AS).
Turns out you can just extend the org.jboss.resteasy.plugins.providers.jackson.ResteasyJackson2Provider without adding/overriding anything so you can register it with a higher priority than the default org.jboss.resteasy.plugins.providers.jackson.ResteasyJackson2Provider picked up from the classpath (which is registered without a priority). This way you ensure your ResteasyJackson2Provider will be chosen over the one picked up via classpath scanning.
Extending to a "custom" ResteasyJackson2Provider:
public class CustomResteasyJackson2Provider extends ResteasyJackson2Provider {
}
Plug that in to the ResteasyClientBuilder with your customized ObjectMapper:
ObjectMapper objectMapper = new ObjectMapper();
// customize your objectMapper here...
CustomResteasyJackson2Provider jacksonProvider = new CustomResteasyJackson2Provider();
jacksonProvider.setMapper(objectMapper); // add objectMapper to provider
// register provider to client
ResteasyClient client = new ResteasyClientBuilder()
.register(jacksonProvider, 100) // any priority over 0 will do
.build();
Hope this helps.