ConcurrentModificationException in sun.net.httpserver.ServerImpl$Dispatcher

The following intermittent exception was observed in the sun.net.httpserver.ServerImpl class when using the HttpServer:

java.util.ConcurrentModificationException
at java.base/java.util.HashMap$HashIterator.nextNode(HashMap.java:1605)
at java.base/java.util.HashMap$KeyIterator.next(HashMap.java:1628)
at jdk.httpserver/sun.net.httpserver.ServerImpl$Dispatcher.run(ServerImpl.java:379)
at java.base/java.lang.Thread.run(Thread.java:1585)