[Apiman-user] Logger exception

Hello, I'm trying to simply replace the NoOpLoggerFactory to SystemOutLogger in apiman.properties and get below exception. It is quite strange as SystemOutLogger is infact implements IDelegateFactory. #apiman-gateway.logger-factory=io.apiman.common.logging.impl.NoOpLoggerFactory apiman-gateway.logger-factory=io.apiman.common.logging.impl.SystemOutLogger Also, If I try to change to Slf4jLoggerFactory, then even the Slf4jLoggerFactory.class is not found. Could you please advise if there is any reference to be added and causes below error. Thanks . Falling back to the Default. [No IDataEncrypter class configured.] 16:50:52,028 ERROR [org.jboss.msc.service.fail] (ServerService Thread Pool -- 69) MSC000001: Failed to start service jboss.undertow.deployment.default-server.default-host./apiman-gateway-api: org.jbos s.msc.service.StartException in service jboss.undertow.deployment.default-server.default-host./apima n-gateway-api: java.lang.RuntimeException: java.lang.ClassCastException: io.apiman.common.logging.impl.SystemOutLogger cannot be cast to io.apiman.common.logging.IDelegateFactory at org.wildfly.extension.undertow.deployment.UndertowDeploymentService$1.run(UndertowDeploym entService.java:85) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) 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) at org.jboss.threads.JBossThread.run(JBossThread.java:320) Caused by: java.lang.RuntimeException: java.lang.ClassCastException: io.apiman.common.logging.impl.SystemOutLogger cannot be cast to io.apiman.common.logging.IDelegateFactory at io.undertow.servlet.core.DeploymentManagerImpl.deploy(DeploymentManagerImpl.java:236) at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.startContext(Undertow DeploymentService.java:100) at org.wildfly.extension.undertow.deployment.UndertowDeploymentService$1.run(UndertowDeploym regards Balu