Hi Team, We are getting this error for the following API https://172.30.X.X/ovirt-engine/api/disks?follow=statistics *But the following API works :* https://172.30.X.X/ovirt-engine/api/vms?follow=statistics *Error in server.log: (when we try to hit to the https://172.30.X.X/ovirt-engine/api/disks?follow=statistics <https://172.30.X.X/ovirt-engine/api/disks?follow=statistics>)* 2018-06-28 13:05:00,393+05 ERROR [io.undertow.request] (default task-2) UT005023: Exception handling request to /ovirt-engine/api/v4/disks: java.lang.RuntimeException: org.jboss.resteasy.spi.UnhandledException: java.lang.IllegalStateException: Problem following 'statistics' link in Disks entity. at io.undertow.servlet.spec.RequestDispatcherImpl.forwardImpl( RequestDispatcherImpl.java:245) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.spec.RequestDispatcherImpl. forwardImplSetup(RequestDispatcherImpl.java:147) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.spec.RequestDispatcherImpl.forward( RequestDispatcherImpl.java:111) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at org.ovirt.engine.api.restapi.invocation.VersionFilter. doFilter(VersionFilter.java:180) [restapi-jaxrs.jar:] at org.ovirt.engine.api.restapi.invocation.VersionFilter. doFilter(VersionFilter.java:98) [restapi-jaxrs.jar:] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl. doFilter(FilterHandler.java:131) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at org.ovirt.engine.api.restapi.invocation.CurrentFilter. doFilter(CurrentFilter.java:117) [restapi-jaxrs.jar:] at org.ovirt.engine.api.restapi.invocation.CurrentFilter. doFilter(CurrentFilter.java:72) [restapi-jaxrs.jar:] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl. doFilter(FilterHandler.java:131) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at org.ovirt.engine.core.aaa.filters.RestApiSessionMgmtFilter. doFilter(RestApiSessionMgmtFilter.java:78) [aaa.jar:] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl. doFilter(FilterHandler.java:131) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at org.ovirt.engine.core.aaa.filters.EnforceAuthFilter. doFilter(EnforceAuthFilter.java:42) [aaa.jar:] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl. doFilter(FilterHandler.java:131) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at org.ovirt.engine.core.aaa.filters.SsoRestApiNegotiationFilter. doFilter(SsoRestApiNegotiationFilter.java:84) [aaa.jar:] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl. doFilter(FilterHandler.java:131) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at org.ovirt.engine.core.aaa.filters.SsoRestApiAuthFilter. doFilter(SsoRestApiAuthFilter.java:47) [aaa.jar:] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl. doFilter(FilterHandler.java:131) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at org.ovirt.engine.core.aaa.filters.SessionValidationFilter. doFilter(SessionValidationFilter.java:59) [aaa.jar:] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl. doFilter(FilterHandler.java:131) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at org.ovirt.engine.core.aaa.filters. RestApiSessionValidationFilter.doFilter(RestApiSessionValidationFilter.java:35) [aaa.jar:] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl. doFilter(FilterHandler.java:131) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at org.ovirt.engine.api.restapi.security.CSRFProtectionFilter. doFilter(CSRFProtectionFilter.java:111) [restapi-jaxrs.jar:] at org.ovirt.engine.api.restapi.security.CSRFProtectionFilter. doFilter(CSRFProtectionFilter.java:102) [restapi-jaxrs.jar:] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl. doFilter(FilterHandler.java:131) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at org.ovirt.engine.core.utils.servlet.CORSSupportFilter. doFilter(CORSSupportFilter.java:284) [utils.jar:] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl. doFilter(FilterHandler.java:131) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.security. ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.security. SSLInformationAssociationHandler.handleRequest( SSLInformationAssociationHandler.java:131) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.security. ServletAuthenticationCallHandler.handleRequest( ServletAuthenticationCallHandler.java:57) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.security.handlers.AuthenticationConstraintHandle r.handleRequest(AuthenticationConstraintHandler.java:53) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.security.handlers.AbstractConfidentialityHandler .handleRequest(AbstractConfidentialityHandler.java:46) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.security. ServletConfidentialityConstraintHandler.handleRequest( ServletConfidentialityConstraintHandler.java:64) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.security. ServletSecurityConstraintHandler.handleRequest( ServletSecurityConstraintHandler.java:59) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.security.handlers.AuthenticationMechanismsHandle r.handleRequest(AuthenticationMechanismsHandler.java:60) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.security. CachedAuthenticatedSessionHandler.handleRequest( CachedAuthenticatedSessionHandler.java:77) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.security.handlers.NotificationReceiverHandler. handleRequest(NotificationReceiverHandler.java:50) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.security.handlers.AbstractSecurityContextAssocia tionHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at org.wildfly.extension.undertow.security.jacc. JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.ServletInitialHandler. handleFirstRequest(ServletInitialHandler.java:292) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.ServletInitialHandler.access$ 100(ServletInitialHandler.java:81) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.ServletInitialHandler$2.call( ServletInitialHandler.java:138) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.ServletInitialHandler$2.call( ServletInitialHandler.java:135) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.core.ServletRequestContextThreadSet upAction$1.call(ServletRequestContextThreadSetupAction.java:48) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call( ContextClassLoaderSetupAction.java:43) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at org.wildfly.extension.undertow.security. SecurityContextThreadSetupAction.lambda$create$0( SecurityContextThreadSetupAction.java:105) at org.wildfly.extension.undertow.deployment. UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0( UndertowDeploymentInfoService.java:1508) at org.wildfly.extension.undertow.deployment. UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0( UndertowDeploymentInfoService.java:1508) at org.wildfly.extension.undertow.deployment. UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0( UndertowDeploymentInfoService.java:1508) at io.undertow.servlet.handlers.ServletInitialHandler. dispatchRequest(ServletInitialHandler.java:272) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.ServletInitialHandler.access$ 000(ServletInitialHandler.java:81) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.ServletInitialHandler$1. handleRequest(ServletInitialHandler.java:104) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.server.Connectors.executeRootHandler(Connectors.java:326) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:812) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [rt.jar:1.8.0_161] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [rt.jar:1.8.0_161] at java.lang.Thread.run(Thread.java:748) [rt.jar:1.8.0_161] Caused by: org.jboss.resteasy.spi.UnhandledException: java.lang.IllegalStateException: Problem following 'statistics' link in Disks entity. at org.jboss.resteasy.core.ExceptionHandler. handleApplicationException(ExceptionHandler.java:78) [resteasy-jaxrs-3.0.24.Final.jar:3.0.24.Final] at org.jboss.resteasy.core.ExceptionHandler.handleException(ExceptionHandler.java:222) [resteasy-jaxrs-3.0.24.Final.jar:3.0.24.Final] at org.jboss.resteasy.core.SynchronousDispatcher.writeException( SynchronousDispatcher.java:179) [resteasy-jaxrs-3.0.24.Final. jar:3.0.24.Final] at org.jboss.resteasy.core.SynchronousDispatcher.invoke( SynchronousDispatcher.java:422) [resteasy-jaxrs-3.0.24.Final. jar:3.0.24.Final] at org.jboss.resteasy.core.SynchronousDispatcher.invoke( SynchronousDispatcher.java:213) [resteasy-jaxrs-3.0.24.Final. jar:3.0.24.Final] at org.jboss.resteasy.plugins.server.servlet. ServletContainerDispatcher.service(ServletContainerDispatcher.java:228) [resteasy-jaxrs-3.0.24.Final.jar:3.0.24.Final] at org.jboss.resteasy.plugins.server.servlet. HttpServletDispatcher.service(HttpServletDispatcher.java:56) [resteasy-jaxrs-3.0.24.Final.jar:3.0.24.Final] at org.jboss.resteasy.plugins.server.servlet. HttpServletDispatcher.service(HttpServletDispatcher.java:51) [resteasy-jaxrs-3.0.24.Final.jar:3.0.24.Final] at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) [jboss-servlet-api_3.1_spec-1.0.0.Final.jar:1.0.0.Final] at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:81) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.security. ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62) [undertow-servlet-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.ServletDispatchingHandler. handleRequest(ServletDispatchingHandler.java:36) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.4.18.Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.ServletInitialHandler. dispatchRequest(ServletInitialHandler.java:274) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.handlers.ServletInitialHandler. dispatchToPath(ServletInitialHandler.java:209) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] at io.undertow.servlet.spec.RequestDispatcherImpl.forwardImpl( RequestDispatcherImpl.java:221) [undertow-servlet-1.4.18. Final.jar:1.4.18.Final] ... 73 more Caused by: java.lang.IllegalStateException: Problem following 'statistics' link in Disks entity. at org.ovirt.engine.api.restapi.resource.utils.LinkFollower. fetchData(LinkFollower.java:185) [restapi-jaxrs.jar:] at org.ovirt.engine.api.restapi.resource.utils.LinkFollower. followLink(LinkFollower.java:144) [restapi-jaxrs.jar:] at org.ovirt.engine.api.restapi.resource.utils.LinkFollower. followLinks(LinkFollower.java:132) [restapi-jaxrs.jar:] at org.ovirt.engine.api.restapi.resource.utils.LinkFollower. followLinks(LinkFollower.java:53) [restapi-jaxrs.jar:] at org.ovirt.engine.api.restapi.resource.BaseBackendResource. follow(BaseBackendResource.java:412) [restapi-jaxrs.jar:] at org.ovirt.engine.api.resource.DisksResource.doList(DisksResource.java:222) [restapi-definition.jar:] at sun.reflect.GeneratedMethodAccessor684.invoke(Unknown Source) [:1.8.0_161] at sun.reflect.DelegatingMethodAccessorImpl.invoke( DelegatingMethodAccessorImpl.java:43) [rt.jar:1.8.0_161] at java.lang.reflect.Method.invoke(Method.java:498) [rt.jar:1.8.0_161] at org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:140) [resteasy-jaxrs-3.0.24.Final.jar:3.0.24.Final] at org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTarget( ResourceMethodInvoker.java:295) [resteasy-jaxrs-3.0.24.Final. jar:3.0.24.Final] at org.jboss.resteasy.core.ResourceMethodInvoker.invoke( ResourceMethodInvoker.java:249) [resteasy-jaxrs-3.0.24.Final. jar:3.0.24.Final] at org.jboss.resteasy.core.ResourceLocatorInvoker. invokeOnTargetObject(ResourceLocatorInvoker.java:138) [resteasy-jaxrs-3.0.24.Final.jar:3.0.24.Final] at org.jboss.resteasy.core.ResourceLocatorInvoker.invoke( ResourceLocatorInvoker.java:101) [resteasy-jaxrs-3.0.24.Final. jar:3.0.24.Final] at org.jboss.resteasy.core.SynchronousDispatcher.invoke( SynchronousDispatcher.java:406) [resteasy-jaxrs-3.0.24.Final. jar:3.0.24.Final] ... 88 more *Caused by: java.lang.IllegalStateException: Problem fetching 'statistics' from Disk* at org.ovirt.engine.api.restapi.resource.utils.LinkFollower. fetchData(LinkFollower.java:219) [restapi-jaxrs.jar:] at org.ovirt.engine.api.restapi.resource.utils.LinkFollower. fetchData(LinkFollower.java:182) [restapi-jaxrs.jar:] ... 102 more *Caused by: java.lang.NullPointerException* at org.ovirt.engine.api.restapi.resource.utils.LinkFollower.getHref(LinkFollower.java:250) [restapi-jaxrs.jar:] at org.ovirt.engine.api.restapi.resource.utils.LinkFollower. fetchData(LinkFollower.java:211) [restapi-jaxrs.jar:] ... 103 more Thanks, Hari