Wildfly 12 Final (RestEASy 3.5 Final) can't discover JsonBindingProvider for Jax-RS ------------------------------------------------------------------------------------ Key: WFLY-10032 URL: https://issues.jboss.org/browse/WFLY-10032 Project: WildFly Issue Type: Bug Components: REST Affects Versions: 12.0.0.Final Reporter: Alessandro Moscatelli Assignee: Alessio Soldano Fix For: 13.0.0.Beta1 Even if started in JavaEE8 Preview Mode : <property name="ee8.preview.mode" value="true"/> Wildfly 12 + RestEasy 3.5 Final can't find this MessageBodyWriter (or Reader) : org.jboss.resteasy.plugins.providers.jsonb.JsonBindingProvider Such is provided inside this dependecy : <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-json-binding-provider</artifactId> <version>3.5.0.Final</version> </dependency> resteasy-json-binding-provider.jar is already provided inside WIldfly 12. RestEASY 3.5 Final documentation stats that JsonBindingProvider should be automatically loaded : RESTEasy JAX-RS If you forcefully exclude Jackson with NoJackson annotation an error will appear stating no MessageWrite is found for json media type when serializing objects for Jax-RS. I debugged a little to try and find out what was happening and I can confirm that in org.jboss.resteasy.spi.ResteasyProviderFactory at row 2592 JsonBindingProvider won't be discovered Can you reproduce/fix this issue ?