diff --git a/integration/admin-client/src/main/java/org/keycloak/admin/client/Keycloak.java b/integration/admin-client/src/main/java/org/keycloak/admin/client/Keycloak.java
index b3cf7ad..2b12225 100755
--- a/integration/admin-client/src/main/java/org/keycloak/admin/client/Keycloak.java
+++ b/integration/admin-client/src/main/java/org/keycloak/admin/client/Keycloak.java
@@ -78,7 +78,7 @@ public class Keycloak {
.connectionPoolSize(10);
if (customJacksonProvider != null) {
- clientBuilder.register(customJacksonProvider);
+ clientBuilder.register(customJacksonProvider, 100);
}
return new Keycloak(serverUrl, realm, username, password, clientId, clientSecret, PASSWORD, clientBuilder.build(), null);
diff --git a/testsuite/integration-arquillian/tests/base/src/main/java/org/keycloak/testsuite/util/AdminClientUtil.java b/testsuite/integration-arquillian/tests/base/src/main/java/org/keycloak/testsuite/util/AdminClientUtil.java
index 316e0ec..d18905a 100644
--- a/testsuite/integration-arquillian/tests/base/src/main/java/org/keycloak/testsuite/util/AdminClientUtil.java
+++ b/testsuite/integration-arquillian/tests/base/src/main/java/org/keycloak/testsuite/util/AdminClientUtil.java
@@ -64,7 +64,9 @@ public class AdminClientUtil {
// We need to ignore unknown JSON properties e.g. in the adapter configuration representation
// during adapter backward compatibility testing
if (ignoreUnknownProperties) {
- jacksonProvider = new ResteasyJackson2Provider();
+ // We need to use anonymous class to avoid the following error from RESTEasy:
+ // Provider class org.jboss.resteasy.plugins.providers.jackson.ResteasyJackson2Provider is already registered. 2nd registration is being ignored.
+ jacksonProvider = new ResteasyJackson2Provider() {};
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
jacksonProvider.setMapper(objectMapper);