to start server part just
mvn clean install wildfly-swarm:run
then you can check e.g. with Postman everything works as expected POST/GET/PUT/DELETE at "http://localhost:8080/concreteEntity"
entity is very simple: { "id": 1002, "concreteEntityProperty": "BlahBlahBlahBlah" }
to start client (while server still running) which creates an entity but fails to read (deserialize json) it from server. Run in client module
mvn clean install -DmainClass=my.pkg.Client exec:java