[keycloak-user] Keycloak Admin Client, create user, error 500, Internal Server Error

[max.catarino at rps.com.br]

I'm using Keycloak 2.5.1 Final, Keycloak Admin Client 2.5.1 Final,
Resteasy Client 3.1.0 Final and Resteasy Jacksom2 Provider 3.1.0 Final.
I'm using the code above to test create an user using the Admin Client.
When the application run the create method, the response returns error
500, Internal Server Error with the trace above on Undertown server. 

I'm missing something? 

Keycloak kc = KeycloakBuilder.builder()

.serverUrl("https://IP:8443/auth/realms/sgp/protocol/openid-connect/auth")
 .realm("testrealm")
 .username(adminUser)
 .password(adminPassword)
 .clientId("admin-cli")
 .resteasyClient(new
ResteasyClientBuilder().connectionPoolSize(10).build())
 .build();

userRep = new UserRepresentation();
userRep.setFirstName("John");
userRep.setLastName("Doe");
userRep.setEmail("john.doe at test.com");
userRep.setEnable(Boolean.TRUE);

Response response = kc.realm(realmId).users().create(userRep); 

17:19:58,337 ERROR [io.undertow.request] (default task-14) UT005023:
Exception handling request to /auth/admin/realms/testrealm/users:
org.jboss.resteasy.spi.UnhandledException:
java.lang.NullPointerException
 at
org.jboss.resteasy.core.ExceptionHandler.handleApplicationException(ExceptionHandler.java:76)
 at
org.jboss.resteasy.core.ExceptionHandler.handleException(ExceptionHandler.java:212)
 at
org.jboss.resteasy.core.SynchronousDispatcher.writeException(SynchronousDispatcher.java:168)
 at
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:411)
 at
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:202)
 at
org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:221)
 at
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
 at
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:51)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
 at
io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
 at
io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
 at
org.keycloak.services.filters.KeycloakSessionServletFilter.doFilter(KeycloakSessionServletFilter.java:90)
 at
io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
 at
io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
 at
io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
 at
io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
 at
io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
 at
org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
 at
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
 at
io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
 at
io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
 at
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
 at
io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
 at
io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
 at
io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
 at
io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
 at
io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
 at
io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
 at
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
 at
org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
 at
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
 at
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
 at
io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
 at
io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
 at
io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
 at
io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
 at
io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
 at
io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:793)
 at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
 at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
 at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
 at
org.keycloak.models.cache.infinispan.UserCacheSession.getUserByUsername(UserCacheSession.java:230)
 at
org.keycloak.services.resources.admin.UsersResource.createUser(UsersResource.java:211)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at
org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:139)
 at
org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTarget(ResourceMethodInvoker.java:295)
 at
org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:249)
 at
org.jboss.resteasy.core.ResourceLocatorInvoker.invokeOnTargetObject(ResourceLocatorInvoker.java:138)
 at
org.jboss.resteasy.core.ResourceLocatorInvoker.invoke(ResourceLocatorInvoker.java:107)
 at
org.jboss.resteasy.core.ResourceLocatorInvoker.invokeOnTargetObject(ResourceLocatorInvoker.java:133)
 at
org.jboss.resteasy.core.ResourceLocatorInvoker.invoke(ResourceLocatorInvoker.java:107)
 at
org.jboss.resteasy.core.ResourceLocatorInvoker.invokeOnTargetObject(ResourceLocatorInvoker.java:133)
 at
org.jboss.resteasy.core.ResourceLocatorInvoker.invoke(ResourceLocatorInvoker.java:101)
 at
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:395)
 ... 37 more