Lot of javax.servlet error in log

Setup, Configuration and Use Runtime
1
  • Platform information:
    • Hardware: RPI B+
    • openHAB version: 2.2.0

Hi,
I upgrade my Openhab 2.1 to 2.2 version last day. The system work quite good, but I always get the following WARN in the log file:

2018-02-04 21:16:31.095 [WARN ] [org.eclipse.jetty.server.HttpChannel] - //192.168.0.10:8080/rest/sitemaps/events/895747f6-4ae3-479c-b36f-6442daae9371?sitemap=custom&pageid=custom
javax.servlet.ServletException: javax.servlet.ServletException: java.lang.UnsupportedOperationException: Asynchronous processing not supported on Servlet 2.x container.
        at org.ops4j.pax.web.service.jetty.internal.JettyServerHandlerCollection.handle(JettyServerHandlerCollection.java:88) [191:org.ops4j.pax.web.pax-web-jetty:6.0.7]
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134) [87:org.eclipse.jetty.server:9.3.22.v20171030]
        at org.eclipse.jetty.server.Server.handle(Server.java:534) [87:org.eclipse.jetty.server:9.3.22.v20171030]
        at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:333) [87:org.eclipse.jetty.server:9.3.22.v20171030]
        at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251) [87:org.eclipse.jetty.server:9.3.22.v20171030]
        at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:283) [79:org.eclipse.jetty.io:9.3.22.v20171030]
        at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:108) [79:org.eclipse.jetty.io:9.3.22.v20171030]
        (... lot of rows)
        ... 13 more

Dou you have any idea what it means?