JSON-P is a Jakarta EE parsing API. RESTEasy provides an archive for it. It has support for JsonObject, JsonArray, and JsonStructure as request or response entities. It should not conflict with Jackson if it is on the classpath too. RESTEasy's provider is provided by default in WildFly. If using another server, use this maven dependency.
<dependency>
<groupId>org.jboss.resteasy</groupId>
<artifactId>resteasy-json-p-provider</artifactId>
<version>6.2.6.Final</version>
</dependency>