JBoss fails to start with ENABLE_MODELER set to true due to a NullPointerException in Registry.registerComponent

Issue

• JBoss randomly fails to start our web connectors sometimes with ENABLE_MODELER set to true due to a NullPointerException in Registry.registerComponent:

ERROR [org.apache.tomcat.util.modeler] (MSC service thread 1-119) JBWEB003104: Error registering MBean jboss.web:type=GlobalRequestProcessor,name=ajp--0.0.0.0-8009: java.lang.NullPointerException
    at org.apache.tomcat.util.modeler.Registry.registerComponent(Registry.java:791) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
    at org.apache.coyote.ajp.AjpProtocol.start(AjpProtocol.java:174) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
    at org.apache.catalina.connector.Connector.start(Connector.java:1049) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
    at org.jboss.as.web.WebConnectorService.start(WebConnectorService.java:274) [jboss-as-web-7.2.0.Final-redhat-8.jar:7.2.0.Final-redhat-8]
    at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1811) [jboss-msc-1.0.4.GA-redhat-1.jar:1.0.4.GA-redhat-1]
    at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1746) [jboss-msc-1.0.4.GA-redhat-1.jar:1.0.4.GA-redhat-1]
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) [rt.jar:1.6.0_38-internal]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [rt.jar:1.6.0_38-internal]
    at java.lang.Thread.run(Thread.java:662) [rt.jar:1.6.0_38-internal]