[ https://issues.jboss.org/browse/WFLY-10616?page=com.atlassian.jira.plugin... ] R Searls commented on WFLY-10616: --------------------------------- There was a code change between wfly-12 and wfly-13 in order to be compliant with the jax-rs 2.1 specification. *This is not a bug*. Resteasy provides a means to designate use of Jackson in liu of JSON-P. Here is the documentation provided in the Resteasy's doc, chapter, "JAX-RS 2.1 Additions". {code:java} RESTEasy supports both JSON-B and JSON-P. In accordance with the specification, entity providers for JSON-B take precedence over those for JSON-P for all types except JsonValue and its sub-types. The support for JSON-B is provided by the JsonBindingProvider from resteasy-json-binding-provider module. To satisfy JAX-RS 2.1 requirements, JsonBindingProvider takes precedence over the other providers for dealing with JSON payloads, in particular the Jackson one. The JSON outputs (for the same input) from Jackson and JSON-B reference implementation can be slightly different. As a consequence, in order to allow retaining backward compatibility, RESTEasy offers a resteasy.preferJacksonOverJsonB context property that can be set to true to disable JsonBindingProvider for the current deloyment. WildFly 14 supports specifying the default value for the resteasy.preferJacksonOverJsonB context property by setting a system property with the same name. Moreover, if no value is set for the context and system properties, it scans JAX-RS deployments for Jackson annotations and sets the property to true if any of those annotations is found. {code} I used the following cmd to set the flag {code:java} ./bin/standalone.sh -Dresteasy.preferJacksonOverJsonB=true {code} Alternatively you can provide a web.xml file with the flag. {code:java} <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <context-param> <param-name>resteasy.preferJacksonOverJsonB</param-name> <param-value>true</param-value> </context-param> </web-app> {code} -- This message was sent by Atlassian JIRA (v7.5.0#75005)