Tomcat shutdown logs 'ClassCastException: class java.io.ObjectStreamClass$Caches$1 cannot be cast to class java.util.Map' Warning

Issue

• After updating to java 11.0.16+, we began seeing the following WARNINGs when stopping tomcat:

WARNING [Thread-3] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesObjectStreamClassCaches Failed to clear soft references from ObjectStreamClass$Caches for web application [ROOT]
    java.lang.ClassCastException: class java.io.ObjectStreamClass$Caches$1 cannot be cast to class java.util.Map (java.io.ObjectStreamClass$Caches$1 and java.util.Map are in module java.base of loader 'bootstrap')
        at org.apache.catalina.loader.WebappClassLoaderBase.clearCache(WebappClassLoaderBase.java:2325)
        at org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesObjectStreamClassCaches(WebappClassLoaderBase.java:2300)
        at org.apache.catalina.loader.WebappClassLoaderBase.clearReferences(WebappClassLoaderBase.java:1669)
        at org.apache.catalina.loader.WebappClassLoaderBase.stop(WebappClassLoaderBase.java:1597)
        at org.apache.catalina.loader.WebappLoader.stopInternal(WebappLoader.java:463)
        at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:257)
        at org.apache.catalina.core.StandardContext.stopInternal(StandardContext.java:5515)
        at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:257)