[keycloak-user] Admin Client

Hi, I'm trying to use the keycloak-admin-client. Keycloak kc = KeycloakBuilder.builder() .serverUrl(serverUrl) .realm("master") .username("username") .password("password") .clientId("admin-cli") .resteasyClient(new ResteasyClientBuilder().connectionPoolSize(10).build()) .build(); UserRepresentation user = kc.realm(realm) .users() .get("userId") .toRepresentation(); But returns an error: Caused by: java.lang.LinkageError: loader constraint violation: loader (instance of org/jboss/modules/ModuleClassLoader) previously initiated loading for a different type with name "org/keycloak/representations/idm/RealmRepresentation" Any ideas? Thanks, Bruno