High CPU in JSF ViewScopeManager.destroyBeans

Issue

• We see high CPU in the ContainerBackgroundProcessor thread when it is calling ViewScopeManager.destroyBeans for a session expiration event:

 "ContainerBackgroundProcessor[StandardEngine[jboss.web]]" daemon prio=10 tid=0x00007ff12c02e800 nid=0x2a84 runnable [0x00007ff17922d000]
    java.lang.Thread.State: RUNNABLE
    at java.util.concurrent.ConcurrentHashMap.hash(ConcurrentHashMap.java:333)
    at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:988)
    at com.sun.faces.mgbean.BeanManager.destroy(BeanManager.java:280)
    at com.sun.faces.application.view.ViewScopeManager.destroyBeans(ViewScopeManager.java:139)
    at com.sun.faces.application.view.ViewScopeManager.sessionDestroyed(ViewScopeManager.java:296)
    at com.sun.faces.application.WebappLifecycleListener.sessionDestroyed(WebappLifecycleListener.java:171)
    at com.sun.faces.config.ConfigureListener.sessionDestroyed(ConfigureListener.java:373)
    at org.apache.catalina.session.StandardSession.expire(StandardSession.java:681)
    - locked <0x0000000767c44f20> (a org.apache.catalina.session.StandardSession)
    at org.apache.catalina.session.StandardSession.isValid(StandardSession.java:576)
    at org.apache.catalina.session.ManagerBase.processExpires(ManagerBase.java:382)
    at org.apache.catalina.session.ManagerBase.backgroundProcess(ManagerBase.java:367)
    at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1302)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1588)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1600)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1600)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1574)
    at java.lang.Thread.run(Thread.java:744)